Zoom lens system

ABSTRACT

In a zoom lens system in which the movement locus of a focusing lens unit is defined by synthesizing a focus cam and a zoom compensation cam, when the sensitivity of movement of an image point in association with the movement, in the direction of the optical axis, of the focusing lens unit in a closest in-focus state is larger than that in an infinity in-focus state, the ratio of the amount of rotation for focusing upon focusing from the infinity position to the closest distance position to the amount of rotation for zooming from the wide-angle end to the telephoto end in the focus cam is set to fall within a predetermined range, so that the sensitivity of movement of an image point in association with the movement, in the direction of rotation, of the focusing lens unit satisfies a specific condition.

The entire disclosure of Japanese Patent Application No. 8-45222including specification, claims, drawings and summary is incorporatedherein by reference in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a zoom lens and, more particularly, toa zoom lens attached to a so-called auto-focusing camera, video camera,or the like, which has a focus detection device, and moves a focusinglens unit in a photographing optical system in accordance with thedetected defocus amount.

2. Related Background Art

In recent years, along with the wide spread use of auto-focusingcameras, various focusing systems such as a so-called inner focusingsystem, rear focusing system, and the like have been examined to make afocusing lens of a zoom lens compact.

However, in general, when a focusing system other than a so-called frontfocusing system is adopted, the lens driving amount for focusing changesupon a change in focal length.

To solve this problem, Japanese Patent Application Laid-Open Nos.4-293008 and 5-142475 assigned to the same assignee as the presentinvention proposed a method of realizing a so-called manual focusingoperation in a zoom lens having a plurality of lens units including afocusing lens unit having both zooming and focusing functions. In thismethod, when a predetermined movement locus for zooming is expressed bythe amount of movement of the lens units in the direction of the opticalaxis and the angle of rotation of a rotatable lens barrel, the movementlocus of the focusing lens unit is defined by synthesizing a focus camand a zoom compensation cam. With this arrangement, even when the amountof movement for focusing along the optical axis changes depending on thezooming state, the angle of rotation of the rotatable lens barrel forfocusing is left unchanged, thus achieving a manual focusing operation.

However, when the above-mentioned zoom lens is applied to anauto-focusing camera system, which comprises focus detection means,storage means for storing the conversion coefficient γ and thecorrection coefficient ε used for calculating the lens driving amount Δxfor focusing the focusing lens unit on the basis of the detected defocusamount ΔBf of a photographing optical system, and calculation means forcalculating the lens driving amount Δx for focusing using the defocusamount ΔBf, the conversion coefficient γ, and the correction coefficientε, problems associated with the storage capacity, calculation error, andthe like are posed.

As in Japanese Patent Application Laid-Open Nos. 4-293008 and 5-142475above, in a zoom lens disclosed in Japanese Patent Application Laid-OpenNos. 57-37307, 57-37308, 63-49715, 63-314511, 3-144411, 3-235908,3-249717, 4-184402, 4-184403, 4-184404, 4-184405, 4-184406, 4-186207,4-186208, 7-110446, and the like, in each of which the movement locus ofthe focusing lens unit is defined by synthesizing a focus cam and a zoomcompensation cam, the above-mentioned problems concerning the storagecapacity, calculation error, and the like have not been examined,either.

Furthermore, in a zoom lens disclosed in Japanese Patent ApplicationLaid-Open Nos. 57-4018, 58-137812, 58-137814, 58-144808, 58-149014,58-150925, and the like, each of which utilizes only a focus cam, theproblems of the storage capacity, calculation error, and the like havenot been examined, either.

On the other hand, as in Japanese Patent Application Laid-Open Nos.63-163808, 1-154014, and the like assigned to the same assignee as thepresent invention, in a zoom lens disclosed in Japanese PatentApplication Laid-Open Nos. 64-35515, 64-35516, 4-140704, and the like,each of which commonly uses a single cam as both a focus cam and a zoomcam, the above-mentioned problems of the storage capacity, calculationerror, and the like have not been examined, either. In addition, thezoom lens disclosed in these references has a basic structure differentfrom that of the present invention since it does not require any zoomcompensation cam, and does not take a so-called flexible manual focusingoperation into account, which has been examined in Japanese PatentApplication Laid-Open Nos. 4-293008, 5-142475, and the like.

A zoom lens disclosed in Japanese Patent Application Laid-Open Nos.2-256011 and 3-101707 which have been assigned to the same assignee asthe present invention, and Japanese Patent Application Laid-Open No.7-120662 which discloses a technical content similar to those disclosedin the above Japanese Patent Application Laid-Open Nos. 2-256011 and3-101707, has a basic structure different from that of the presentinvention since it realizes zooming by a relative movement, in thedirection of rotation of a lens barrel, between a focus cam and a zoomcam, and focusing by a relative movement in the direction of the opticalaxis, and does not examine an auto-focusing operation at all.

Similarly, in Japanese Patent Application Laid-Open No. 7-5362, a zoomlens disclosed therein has a basic structure different from that of thepresent invention since the amount of movement for focusing is to bedefined by synthesizing two kinds of cams without using a focus camdirectly, and the above-mentioned problems concerning the storagecapacity, calculation error, and the like have not been examined.

Furthermore, Japanese Patent Application Laid-Open Nos. 61-77027,1-232313, and the like discloses a lens system having a focus cam so asto realize an accurate auto-focusing operation with a small calculationerror. However, these references relate to a single-focus lens having nozooming function, and cannot be applied to a focus cam required toachieve a so-called manual focusing operation in a zoom lens in whichthe amount of movement in the direction of the optical axis for focusingchanges depending on the zooming state.

The principle of the auto-focus operation will be briefly describedbelow.

An auto-focusing system disclosed in Japanese Patent ApplicationLaid-Open Nos. 62-78519, 62-170924, 1-131507, 1-131508, 1-131509,3-228006, and the like, comprises focus detection means, calculationmeans for calculating the lens driving amount for focusing, and storagemeans for storing specific constants used in calculations. In thissystem, the focus detection means detects the defocus amount ΔBf betweenthe imaging position of an actual object by the photographing opticalsystem and a predetermined imaging point position, and the calculationmeans for calculating the lens driving amount for focusing calculatesthe lens driving amount Δx for focusing on the basis of the detecteddefocus amount ΔBf of the photographing optical system, thus achievingan auto-focusing operation.

If the relationship between the lens driving amount Δx for focusing andthe defocus amount ΔBf is expressed using a conversion coefficient Kassociated with focusing as follows:

    Δx=ΔBf/K

then, the lens driving amount Δx can be calculated by setting theconversion coefficient K.

However, as described in Japanese Patent Application Laid-Open No.62-170924, the conversion coefficient K changes in correspondence notonly with the focal length but also with the object position and lensarrangement.

Therefore, as described in Japanese Patent Application Laid-Open Nos.62-78519, 62-170924, and the like, using the conversion coefficient γdefined as the ratio (sensitivity) of the amount of infinitesimalmovement of the imaging plane with respect to the amount ofinfinitesimal movement of the focusing lens unit in the vicinity of apredetermined in-focus point, and the correction coefficient ε forcorrecting the conversion coefficient in accordance with the defocusamount ΔBf, the conversion coefficient K is calculated by the followingformulas:

    K=γ+ε·f(ΔBf)

    K=γ+ε·ΔBf.sup.2 in Japanese Patent Application Laid-Open No. 62-78519

    K=γ(1+ε·ΔBf) in Japanese Patent Application Laid-Open No. 62-170924

and thereafter, the lens driving amount Δx is calculated based on theconversion coefficient K.

(Of course, the lens driving amount Δx for focusing may be directlycalculated from the defocus amount ΔBf using the conversion coefficientγ and the correction coefficient ε.)

Furthermore, in a photographing system having a zooming optical system,since the values of the conversion coefficient γ and the correctioncoefficient ε change depending on the lens arrangement, a plurality ofpairs of data of the conversion coefficient γ and the correctioncoefficient ε are stored in the storage means in units of a plurality ofdivided zoom ranges and focus ranges, as described in Japanese PatentApplication Laid-Open No. 3-228006.

In other words, in the photographing system having the zooming opticalsystem, the focus detection means detects the defocus amount ΔBf causedby the zooming optical system, and values of the conversion coefficientγ and the correction coefficient ε corresponding to the zoom and focuspositions respectively detected by zoom and focus position detectionmeans are read out from the storage means. The calculation means forcalculating the lens driving amount for focusing calculates the lensdriving amount Δx for focusing using the defocus amount ΔBf, theconversion coefficient γ, and the correction coefficient ε, and drivingmeans drives a lens by the calculated lens driving amount Δx forfocusing, thus achieving a focusing operation.

However, in a normal focusing mechanism using a helicoid mechanism or acam mechanism, the lens driving amount for focusing must be describednot as a lens driving amount Δx in the direction of the optical axis butas a lens driving amount Δa in the direction of rotation.

Therefore, when the relationship between the lens driving amount Δx andthe defocus amount ΔBf in the direction of the optical axis is convertedinto the relationship between the lens driving amount Δa and the defocusamount ΔBf in the direction of rotation using a conversion coefficientK_(a) associated with the direction of rotation, we have:

    Δa=ΔBf/K.sub.a

If conversion coefficient K associated with the direction of the opticalaxis is newly defined as K_(x), the conversion coefficient K_(a)associated with the direction of rotation is expressed using aconversion coefficient Φ between the lens driving amount Δx in thedirection of the optical axis and the lens driving amount Δa in thedirection of rotation as follows:

    K.sub.a =K.sub.x ·Φ

Thus, the formula in Japanese Patent Application Laid-Open No. 62-170924is modified to a formula associated with the conversion coefficientK_(a) in the direction of rotation as follows:

    K.sub.a =Φγ(1+ε·ΔBf)

If Δx and Δa have a linear relationship therebetween like in a helicoidmechanism, Φ becomes a constant. However, when a cam mechanism is used,the conversion coefficient Φ changes depending on the cam shape. Theconversion coefficient Φ can be replaced by a slope (dx/da) defined bythe cam shape as follows:

    K.sub.a =γ·(dx/da)(1+ε·ΔBf)

The conversion coefficient γ and the correction coefficient ε in aninner focusing type zoom lens disclosed in Japanese Patent ApplicationLaid-Open Nos. 4-293008, 5-142475, and the like will be examined below.

When a zoom lens system is constituted by n lens units, and its k-thlens unit is used as the focusing lens unit, if the ratio of the amountdBf of infinitesimal movement of the imaging plane to the amount dx ofinfinitesimal movement, in the direction of the optical axis, of thefocusing lens unit, i.e., the conversion coefficient γ (dBf/dx: thesensitivity associated with movement in the direction of the opticalaxis) is defined as a new conversion coefficient γ_(x) associated withthe amount x of movement in the direction of the optical axis, theconversion coefficient γ_(x) can be expressed using the imagingmagnifications β of the respective lens units as follows:

    γ.sub.x =(1-β.sub.k.sup.2)β.sub.k+1.sup.2 β.sub.k+2.sup.2. . . β.sub.n.sup.2

Therefore, the rate of change, from the infinity in-focus value (γ_(x0))to the closest in-focus value (γ_(xR)), of the conversion coefficientγ_(x) associated with the amount x of movement in the direction of theoptical axis can be expressed using the imaging magnifications β_(0k)and β_(Rk) of the focusing lens unit at the infinity and closestin-focus points as follows:

    γ.sub.xR /γ.sub.x0 =(1-β.sub.Rk.sup.2)/(1-β.sub.0k.sup.2)

Furthermore, if the ratio of the amount dBf of infinitesimal movement ofthe imaging plane to the angle da of infinitesimal rotation of thefocusing lens unit (dBf/da: the sensitivity associated with movement inthe direction of rotation) is defined as a new conversion coefficientγ_(a) associated with the angle a of rotation of a rotatable lensbarrel, the conversion coefficient γ_(a) associated with the angle a ofrotation of the rotatable lens barrel can be expressed by:

    γ.sub.a =γ.sub.x ·(dx/da)

where dx/da is the slope of the focus cam.

Therefore, the rate of change, from the infinity in-focus value (γ_(a0))to the closest in-focus value (γ_(aR)), of the conversion coefficientγ_(a) associated with the angle a of rotation of the rotatable lensbarrel can be expressed using slopes (dx/da)₀ and (dx/da)_(R) at theinfinity and closest corresponding positions on the focus cam asfollows:

    γ.sub.aR /γ.sub.a0 =(γ.sub.xR /γ.sub.x0)·((dx/da).sub.R /(dx/da).sub.0)

The rate of change of the conversion coefficient γ_(x) with respect tothe amount x of movement in the direction of the optical axis and therate of change of the conversion coefficient γ_(a) with respect to theangle a of rotation of the rotatable lens barrel will be examined belowin association with an embodiment which is the same as the firstembodiment of the present invention except for the fact that therotation amount ratio (a_(F) /a_(Z)) of the rotation amount for focusingfrom the infinity in-focus position to the closest in-focus position tothe amount of rotation for zooming from the wide-angle end to thetelephoto end is set to be 1.0 similarly to an embodiment of JapanesePatent Application Laid-Open No. 5-142475. Note that the amount ofrotation for zooming from the wide-angle end to the telephoto end andthe amount of rotation for focusing are respectively re-set to be 10.0for the purpose of a comparison with an embodiment of the presentinvention.

Table 1 below summarizes various paraxial data of an optical system anddata for defining the shape of the focus cam of the embodiment which isthe same as the first embodiment of the present invention except for thefact that the rotation amount ratio (a_(F) /a_(Z)) of the rotationamount for focusing from the infinity infocus position to the closestin-focus position to the amount of rotation for zooming from thewide-angle end to the telephoto end is set to be 1.0 similarly to theembodiment of Japanese Patent Application Laid-Open No. 5-142475(hereinafter referred to as "comparative embodiment").

The upper table in Table 1 summarizes the focal length data andprincipal point interval data of the respective lens units of theoptical system corresponding to the comparative embodiment. In thistable, F1, F2, F3, F4, and F5 are respectively the focal lengths offirst, second, third, fourth, and fifth lens units, and D1, D2, D3, D4,and D5 are respectively the principal point interval between the firstand second lens units, the principal point interval between the secondand third lens units, the principal point interval between the third andfourth lens units, the principal point interval between the fourth andfifth lens units, and the principal point interval between the fifthlens unit and a predetermined imaging plane in six zooming states (focallengths F=28.8 (1-POS), 35.0 (2-POS), 50.0 (3-POS), 70.0 (4-POS), 95.0(5-POS), and 126.0 mm (6-POS)).

The middle table in Table 1 summarizes spline sample point data when theshape of the focus cam in the fourth lens unit which is used forfocusing is expressed by a spline function associated with the angle aof rotation of the rotatable lens barrel and the amount x of movement inthe direction of the optical axis (complying with "Numerical Analysisand FORTRAN", MARUZEN, "Spline Function and Its Applications", KyoikuShuppan, and the like). In this middle table, (1), (2), (3), (4), and(5) correspond to the first, second, third, fourth, and fifth lensunits, respectively.

Furthermore, the lower table in Table 1 summarizes the infinity focusingpositions (infinity corresponding positions) at the respective focallengths (F=28.8, 35.0, 50.0, 70.0, 95.0, and 126.0 mm), and the amountsof rotation (amounts of rotation for focusing) upon focusing torespective photographing distances (R=5.0, 3.0, 2.0, 1.5, 1.0, and 0.8m) using the focus cam. Since both the amount of rotation for zoomingfrom the wide-angle end (F=28.8) to the telephoto end (F=126.0) and theamount of rotation for focusing from the infinity in-focus position tothe closest in-focus position (R=0.80 m) are 10.0, the rotation amountratio (a_(F) /a_(Z)) of the amount of rotation for focusing to theamount of rotation for zooming is 1.0.

                                      TABLE 1                                     __________________________________________________________________________    Comparative Embodiment f = 28.8 to 126.0                                      (Rotation Amount Ratio: a.sub.F /a.sub.Z = 1.00)                              __________________________________________________________________________    Focal lengths and Principal Point Intervals of Lens Units of Comparative      Embodiment                                                                               1-POS                                                                             2-POS                                                                              3-POS                                                                             4-POS                                                                              5-POS                                                                             6-POS                                        __________________________________________________________________________            F  28.8000                                                                           35.0000                                                                            50.0000                                                                           70.0000                                                                            95.0000                                                                           126.0000                                     F1 98.0000                                                                            D1 9.3696                                                                            15.5678                                                                            26.0774                                                                           35.1343                                                                            42.9607                                                                           49.3378                                      F2 -20.2000                                                                           D2 34.5121                                                                           30.5093                                                                            24.1872                                                                           19.0594                                                                            14.7856                                                                           10.6994                                      F3 21.3000                                                                            D3 8.9319                                                                            9.5307                                                                             10.6727                                                                           11.7442                                                                            12.4611                                                                           13.1911                                      F4 -19.6000                                                                           D4 14.4820                                                                           13.8832                                                                            12.7412                                                                           11.6697                                                                            10.9528                                                                           10.2228                                      F5 35.5000                                                                            D5 49.8013                                                                           51.5975                                                                            55.0237                                                                           58.2383                                                                            61.1451                                                                           63.0195                                      __________________________________________________________________________    Focus Cam Shape (Spline Interpolation Sample Point)                           Corresponding to Comparative Embodiment                                            ANGLE                                                                             (1)     (2)                                                                              (3)     (4) (5)                                           __________________________________________________________________________     1   .0000                                                                             .0000   .0000                                                                            .0000   .0000                                                                             .0000                                          2   4.2963                                                                            .0000   .0000                                                                            .0000   -.0524                                                                            .0000                                          3   5.6678                                                                            .0000   .0000                                                                            .0000   -.0886                                                                            .0000                                          4   6.8749                                                                            .0000   .0000                                                                            .0000   -.1351                                                                            .0000                                          5   7.8043                                                                            .0000   .0000                                                                            .0000   -.1832                                                                            .0000                                          6   9.1848                                                                            .0000   .0000                                                                            .0000   -.2845                                                                            .0000                                          7   10.0000                                                                           .0000   .0000                                                                            .0000   -.3653                                                                            .0000                                          8   14.2963                                                                           .0000   .0000                                                                            .0000   -1.2787                                                                           .0000                                          9   15.6678                                                                           .0000   .0000                                                                            .0000   -1.9076                                                                           .0000                                         10   16.8749                                                                           .0000   .0000                                                                            .0000   -2.7174                                                                           .0000                                         11   17.8043                                                                           .0000   .0000                                                                            .0000   -3.5551                                                                           .0000                                         12   19.1848                                                                           .0000   .0000                                                                            .0000   -5.3209                                                                           .0000                                         13   20.000                                                                            .0000   .0000                                                                            .0000   -6.7318                                                                           .0000                                         __________________________________________________________________________    Amount of Rotation for Zooming and                                            Amount of Rotation for Focusing of Comparative Embodiment                     (Rotation Amount Ratio: a.sub.F /a.sub.Z = 1.00)                                      Infinity                                                                      Corresponding                                                                          Photographing                                                                            Amount of Rotation                                Focal Length                                                                          Position Distance   for Focusing                                      __________________________________________________________________________     28.8 mm                                                                               .0000    5.00 m     4.296                                             35.0 mm                                                                               1.3838   3.00 m     5.668                                             50.0 mm                                                                               3.7931   2.00 m     6.875                                             70.0 mm                                                                               6.0270   1.50 m     7.804                                             95.0 mm                                                                               8.0868   1.00 m     9.185                                            126.0 mm                                                                              10.0000   0.80 m    10.000                                            Condition Corresponding Value (1)                                                               1.31                                                        Condition Corresponding Value (2)                                                              17.44                                                        Condition Corresponding Value (3)                                                               1.00                                                        Condition Corresponding Value (4)                                                              14.24 (wide-angle end)                                                                   21.70 (telephoto end)                             Condition Corresponding Value (5)                                                               4.76 (wide-angle end)                                                                    6.58 (telephoto end)                             Condition Corresponding Value (6)                                                               0.34 (wide-angle end)                                                                    0.28 (telephoto end)                             __________________________________________________________________________

Table 2 below summarizes the numerical value data of the cams of thefocusing lens unit in the comparative embodiment, which data arecalculated by interpolation based on a spline function on the basis ofthe sample data of the focus cam summarized in the middle table inTable 1. In this table, (ANGLE) is the angle of rotation of therotatable lens barrel, (4) is the amount (mm) of movement, in thedirection of the optical axis, of the fourth lens unit, and (F) is thefocal length (mm) of the entire system in an infinity in-focus statecorresponding to the amount (ANGLE) of rotation.

                  TABLE 2                                                         ______________________________________                                        Cam Numerical Value Data of Focusing Lens Unit                                in Comparative Embodiment                                                                           Zoom Compensation                                       Focus Cam Numerical Value Data                                                                      Cam Numerical Value Data                                ANGLE  (4)     F          ANGLE (4)     F                                     ______________________________________                                        .0000  .0000   28.8000    .0000 .0000   28.8000                               .5000  -.0039  30.8977    .5000 .4276   30.8977                               1.0000 -.0079  33.1447    1.0000                                                                              .8636   33.1447                               1.5000 -.0124  35.5868    1.5000                                                                              1.3155  35.5868                               2.0000 -.0173  38.2569    2.0000                                                                              1.7855  38.2569                               2.5000 -.0231  41.1789    2.5000                                                                              2.2688  41.1789                               3.0000 -.0297  44.3685    3.0000                                                                              2.7579  44.3685                               3.5000 -.0374  47.8358    3.5000                                                                              3.2440  47.8358                               4.0000 -.0464  51.5859    4.0000                                                                              3.7188  51.5859                               4.5000 -.0569  55.6175    4.5000                                                                              4.1839  55.6175                               5.0000 -.0691  59.9543    5.0000                                                                              4.6556  59.9543                               5.5000 -.0833  64.6457    5.5000                                                                              5.1530  64.6457                               6.0000 -.0998  69.7157    6.0000                                                                              5.6946  69.7157                               6.5000 -.1189  75.1502    6.5000                                                                              6.2879  75.1502                               7.0000 -.1408  80.9450    7.0000                                                                              6.8895  80.9450                               7.5000 -.1660  87.1351    7.5000                                                                              7.4492  87.1351                               8.0000 -.1951  93.7913    8.0000                                                                              7.9384  93.7913                               8.5000 -.2291  101.0094   8.5000                                                                              8.3526  101.0094                              9.0000 -.2684  108.8867   9.0000                                                                              8.7143  108.8867                              9.5000 -.3139  117.4149   9.5000                                                                              9.0402  117.4149                              10.0000                                                                              -.3653  126.0000   10.0000                                                                             9.3243  126.0000                              10.5000                                                                              -.4227  .0000                                                          11.0000                                                                              -.4879  .0000                                                          11.5000                                                                              -.5633  .0000                                                          12.0000                                                                              -.6511  .0000                                                          12.5000                                                                              -.7536  .0000                                                          13.0000                                                                              -.8731  .0000                                                          13.5000                                                                              -1.0119 .0000                                                          14.0000                                                                              -1.1724 .0000                                                          14.5000                                                                              -1.3569 .0000                                                          15.0000                                                                              -1.5693 .0000                                                          15.5000                                                                              -1.8160 .0000                                                          16.0000                                                                              -2.1031 .0000                                                          16.5000                                                                              -2.4356 .0000                                                          17.0000                                                                              -2.8180 .0000                                                          17.5000                                                                              -3.2565 .0000                                                          18.0000                                                                              -3.7613 .0000                                                          18.5000                                                                              -4.3476 .0000                                                          19.0000                                                                              -5.0362 .0000                                                          19.5000                                                                              -5.8441 .0000                                                          20.0000                                                                              -6.7318 .0000                                                          ______________________________________                                    

The left table in Table 2 summarizes the numerical value data of thefocus cam in the comparative embodiment, and the right table in Table 2summarizes the numerical value data of the zoom compensation cam of thecomparative embodiment. A value obtained by synthesizing the amount (4)of movement in the direction of the optical axis in the numerical valuedata of the focus cam and the amount (4) of movement in the direction ofthe optical axis in the numerical value data of the zoom compensationcam in a range from the amount of rotation (ANGLE=0.0) to the amount ofrotation (ANGLE=10.0) agrees with the movement locus of the fourth lensunit calculated using the paraxial data in the upper table in Table 1.

Tables 3, 4, and 5 below summarize the amount DX (mm) of movement forfocusing, in the direction of the optical axis, of the focusing lensunit, the imaging magnifications β_(K) of the respective lens units, theconversion coefficient γ_(x) associated with the direction of theoptical axis, the slope (dx/da) of the focus cam, and the conversioncoefficient γ_(a) associated with the direction of rotation at thewide-angle end (F=28.8), the middle position (F=70.0), and the telephotoend (F=126.0), respectively. In these tables, (R) on the left side isthe photographing distance (m), (ANG) is the amount of rotation on thefocus cam upon focusing to the respective photographing distances, and1), 2), 3), 4), and 5) on the right side respectively represent thefirst, second, third, fourth, and fifth lens units. Also, in thesetables, the first table summarizes the amount DX (mm) of movement forfocusing in the direction of the optical axis upon focusing to therespective photographing distances (R=10.0, 5.0, 3.0, 2.0, 1.5, 1.0, and0.8 m) (note that movement toward the object side is positive). Thesecond table summarizes the imaging magnifications β_(K) of therespective lens units in an in-focus state at the respectivephotographing distances (R=10.0, 5.0, 3.0, 2.0, 1.5, 1.0, and 0.8 m).The third table summarizes the conversion coefficient γ_(x) associatedwith the direction of the optical axis of the focusing lens unit in anin-focus state at the respective photographing distances (R=10.0, 5.0,3.0, 2.0, 1.5, 1.0, and 0.8 m). Furthermore, the fourth table summarizesthe slope (dx/da) of the focus cam at the positions, on the focus cam,corresponding to an in-focus state at the respective photographingdistances (R=10.0, 5.0, 3.0, 2.0, 1.5, 1.0, and 0.8 m), and the fifthtable summarizes the conversion coefficient γ_(a) associated with thedirection of rotation of the focusing lens unit in an in-focus state atthe respective photographing distances (R=10.0, 5.0, 3.0, 2.0, 1.5, 1.0,and 0.8 m).

                                      TABLE 3                                     __________________________________________________________________________    Amount DX (mm) of Movement for Focusing in Direction of Optical Axis          at Wide-angle End (28.8 mm) in Comparative Embodiment                         R .000                                                                              ANG                                                                              .000                                                                              1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              .000                                                                              5)                                                                              .000                                      R 10.000                                                                            ANG                                                                              2.729                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              -.026                                                                             5)                                                                              .000                                      R 5.000                                                                             ANG                                                                              4.296                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              -.052                                                                             5)                                                                              .000                                      R 3.000                                                                             ANG                                                                              5.668                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              -.089                                                                             5)                                                                              .000                                      R 2.000                                                                             ANG                                                                              6.875                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              -.135                                                                             5)                                                                              .000                                      R 1.500                                                                             ANG                                                                              7.804                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              -.183                                                                             5)                                                                              .000                                      R 1.000                                                                             ANG                                                                              9.185                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              -.284                                                                             5)                                                                              .000                                      R .800                                                                              ANG                                                                              10.000                                                                            1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              -.365                                                                             5)                                                                              .000                                      Imaging Magnification β.sub.K of Lens Units                              at Wide-angle End (28.8 mm) in Comparative Embodiment                         R .000                                                                              ANG                                                                              .000                                                                              1)                                                                              .000                                                                             2)                                                                              -.295                                                                            3)                                                                              -.541                                                                            4)                                                                              -4.568                                                                            5)                                                                              -.403                                     R 10.000                                                                            ANG                                                                              2.729                                                                             1)                                                                              -.010                                                                            2)                                                                              -.291                                                                            3)                                                                              -.542                                                                            4)                                                                              -4.570                                                                            5)                                                                              -.403                                     R 5.000                                                                             ANG                                                                              4.296                                                                             1)                                                                              -.020                                                                            2)                                                                              -.287                                                                            3)                                                                              -.543                                                                            4)                                                                              -4.571                                                                            5)                                                                              -.403                                     R 3.000                                                                             ANG                                                                              5.668                                                                             1)                                                                              -.035                                                                            2)                                                                              -.281                                                                            3)                                                                              -.545                                                                            4)                                                                              -4.573                                                                            5)                                                                              -.403                                     R 2.000                                                                             ANG                                                                              6.875                                                                             1)                                                                              -.055                                                                            2)                                                                              -.274                                                                            3)                                                                              -.547                                                                            4)                                                                              -4.575                                                                            5)                                                                              -.403                                     R 1.500                                                                             ANG                                                                              7.804                                                                             1)                                                                              -.076                                                                            2)                                                                              -.266                                                                            3)                                                                              -.549                                                                            4)                                                                              -4.578                                                                            5)                                                                              -.403                                     R 1.000                                                                             ANG                                                                              9.185                                                                             1)                                                                              -.125                                                                            2)                                                                              -.250                                                                            3)                                                                              -.554                                                                            4)                                                                              -4.583                                                                            5)                                                                              -.403                                     R .800                                                                              ANG                                                                              10.000                                                                            1)                                                                              -.168                                                                            2)                                                                              -.238                                                                            3)                                                                              -.557                                                                            4)                                                                              -4.587                                                                            5)                                                                              -.403                                     Conversion Coefficient γ.sub.x Associated With Direction of Optical     Axis                                                                          at Wide-angle End (28.8 mm) in Comparative Embodiment                         R .000                                                                              ANG                                                                              .000                                                                              1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              -3.225                                                                            5)                                                                              .000                                      R 10.000                                                                            ANG                                                                              2.729                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              -3.227                                                                            5)                                                                              .000                                      R 5.000                                                                             ANG                                                                              4.296                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              -3.229                                                                            5)                                                                              .000                                      R 3.000                                                                             ANG                                                                              5.668                                                                             1)                                                                              .000                                                                             2)                                                                              .006                                                                             3)                                                                              .000                                                                             4)                                                                              -3.231                                                                            5)                                                                              .000                                      R 2.000                                                                             ANG                                                                              6.875                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              -3.235                                                                            5)                                                                              .000                                      R 1.500                                                                             ANG                                                                              7.804                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              -3.239                                                                            5)                                                                              .000                                      R 1.000                                                                             ANG                                                                              9.185                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              -3.246                                                                            5)                                                                              .000                                      R .800                                                                              ANG                                                                              10.000                                                                            1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              -3.252                                                                            5)                                                                              .000                                      Slope dx/da of Focus Cam                                                      at Wide-angle End (28.8 mm) in Comparative Embodiment                         R .000                                                                              ANG                                                                              .000                                                                              1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              -.008                                                                             5)                                                                              .000                                      R 10.000                                                                            ANG                                                                              2.729                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              -.013                                                                             5)                                                                              .000                                      R 5.000                                                                             ANG                                                                              4.296                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              -.021                                                                             5)                                                                              .000                                      R 3.000                                                                             ANG                                                                              5.668                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              -.032                                                                             5)                                                                              .000                                      R 2.000                                                                             ANG                                                                              6.875                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              -.045                                                                             5)                                                                              .000                                      R 1.500                                                                             ANG                                                                              7.804                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              -.059                                                                             5)                                                                              .000                                      R 1.000                                                                             ANG                                                                              9.185                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              -.089                                                                             5)                                                                              .000                                      R .800                                                                              ANG                                                                              10.000                                                                            1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              -.109                                                                             5)                                                                              .000                                      Conversion Coefficient γ.sub.a Associated With Direction of             Rotation                                                                      at Wide-angle End (28.8 mm) in Comparative Embodiment                         R .000                                                                              ANG                                                                              .000                                                                              1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              .025                                                                              5)                                                                              .000                                      R 10.000                                                                            ANG                                                                              2.729                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              .042                                                                              5)                                                                              .000                                      R 5.000                                                                             ANG                                                                              4.296                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              .069                                                                              5)                                                                              .000                                      R 3.000                                                                             ANG                                                                              5.668                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              .104                                                                              5)                                                                              .000                                      R 2.000                                                                             ANG                                                                              6.875                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              .146                                                                              5)                                                                              .000                                      R 1.500                                                                             ANG                                                                              7.804                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              .192                                                                              5)                                                                              .000                                      R 1.000                                                                             ANG                                                                              9.185                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              .290                                                                              5)                                                                              .000                                      R .800                                                                              ANG                                                                              10.000                                                                            1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              .353                                                                              5)                                                                              .000                                      __________________________________________________________________________     Condition Corresponding Values: γ.sub.xR /γ.sub.aO = 14.24   

                                      TABLE 4                                     __________________________________________________________________________    Amount DX (mm) of Movement for Focusing in Direction of Optical Axis          at Middle Position (70.0 mm) in Comparative Embodiment                        R .000                                                                              ANG                                                                              .000                                                                              1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              .000                                                                              5)                                                                              .000                                      R 10.000                                                                            ANG                                                                              2.704                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              -.146                                                                             5)                                                                              .000                                      R 5.000                                                                             ANG                                                                              4.237                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              -.294                                                                             5)                                                                              .000                                      R 3.000                                                                             ANG                                                                              5.671                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              -.496                                                                             5)                                                                              .000                                      R 2.000                                                                             ANG                                                                              6.903                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              -.754                                                                             5)                                                                              .000                                      R 1.500                                                                             ANG                                                                              7.822                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              -1.021                                                                            5)                                                                              .000                                      R 1.000                                                                             ANG                                                                              9.204                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              -1.578                                                                            5)                                                                              .000                                      R .800                                                                              ANG                                                                              10.000                                                                            1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              -2.019                                                                            5)                                                                              .000                                      Imaging Magnification β.sub.K of Lens Units                              at Middle Position (70.0 mm) in Comparative Embodiment                        R .000                                                                              ANG                                                                              .000                                                                              1)                                                                              .000                                                                             2)                                                                              -.473                                                                            3)                                                                              -.774                                                                            4)                                                                              -3.044                                                                            5)                                                                              -.641                                     R 10.000                                                                            ANG                                                                              2.704                                                                             1)                                                                              -.010                                                                            2)                                                                              -.463                                                                            3)                                                                              -.780                                                                            4)                                                                              -3.051                                                                            5)                                                                              -.641                                     R 5.000                                                                             ANG                                                                              4.237                                                                             1)                                                                              -.021                                                                            2)                                                                              -.452                                                                            3)                                                                              -.786                                                                            4)                                                                              -3.059                                                                            5)                                                                              -.641                                     R 3.000                                                                             ANG                                                                              5.671                                                                             1)                                                                              -.035                                                                            2)                                                                              -.438                                                                            3)                                                                              -.795                                                                            4)                                                                              -3.069                                                                            5)                                                                              -.641                                     R 2.000                                                                             ANG                                                                              6.903                                                                             1)                                                                              -.055                                                                            2)                                                                              -.420                                                                            3)                                                                              -.806                                                                            4)                                                                              -3.082                                                                            5)                                                                              -.641                                     R 1.500                                                                             ANG                                                                              7.822                                                                             1)                                                                              -.077                                                                            2)                                                                              -.402                                                                            3)                                                                              -.817                                                                            4)                                                                              -3.096                                                                            5)                                                                              -.641                                     R 1.000                                                                             ANG                                                                              9.204                                                                             1)                                                                              -.128                                                                            2)                                                                              -.366                                                                            3)                                                                              -.840                                                                            4)                                                                              -3.124                                                                            5)                                                                              -.641                                     R .800                                                                              ANG                                                                              10.000                                                                            1)                                                                              -.173                                                                            2)                                                                              -.339                                                                            3)                                                                              -.859                                                                            4)                                                                              -3.147                                                                            5)                                                                              -.641                                     Conversion Coefficient γ.sub.x Associated With Direction of Optical     Axis                                                                          at Middle Position (70.0 mm) in Comparative Embodiment                        R .000                                                                              ANG                                                                              .000                                                                              1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              -3.390                                                                            5)                                                                              .000                                      R 10.000                                                                            ANG                                                                              2.704                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              -3.409                                                                            5)                                                                              .000                                      R 5.000                                                                             ANG                                                                              4.237                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              -3.428                                                                            5)                                                                              .000                                      R 3.000                                                                             ANG                                                                              5.671                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              -3.454                                                                            5)                                                                              .000                                      R 2.000                                                                             ANG                                                                              6.903                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              -3.487                                                                            5)                                                                              .000                                      R 1.500                                                                             ANG                                                                              7.822                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              -3.521                                                                            5)                                                                              .000                                      R 1.000                                                                             ANG                                                                              9.204                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              -3.594                                                                            5)                                                                              .000                                      R .800                                                                              ANG                                                                              10.000                                                                            1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              -3.652                                                                            5)                                                                              .000                                      Slope dx/da of Focus Cam                                                      at Middle Position (70.0 mm) in Comparative Embodiment                        R .000                                                                              ANG                                                                              .000                                                                              1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              -.036                                                                             5)                                                                              .000                                      R 10.000                                                                            ANG                                                                              2.704                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              -.078                                                                             5)                                                                              .000                                      R 5.000                                                                             ANG                                                                              4.237                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              -.115                                                                             5)                                                                              .000                                      R 3.000                                                                             ANG                                                                              5.671                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              -.173                                                                             5)                                                                              .000                                      R 2.000                                                                             ANG                                                                              6.903                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              -.252                                                                             5)                                                                              .000                                      R 1.500                                                                             ANG                                                                              7.822                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              -.330                                                                             5)                                                                              .000                                      R 1.000                                                                             ANG                                                                              9.204                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              -.490                                                                             5)                                                                              .000                                      R .800                                                                              ANG                                                                              10.000                                                                            1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              -.623                                                                             5)                                                                              .000                                      Conversion Coefficient γ.sub.a Associated With Direction of             Rotation                                                                      at Middle Position (70.0 mm) in Comparative Embodiment                        R .000                                                                              ANG                                                                              .000                                                                              1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              .122                                                                              5)                                                                              .000                                      R 10.000                                                                            ANG                                                                              2.704                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              .267                                                                              5)                                                                              .000                                      R 5.000                                                                             ANG                                                                              4.237                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              .394                                                                              5)                                                                              .000                                      R 3.000                                                                             ANG                                                                              5.671                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              .596                                                                              5)                                                                              .000                                      R 2.000                                                                             ANG                                                                              6.903                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              .879                                                                              5)                                                                              .000                                      R 1.500                                                                             ANG                                                                              7.822                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              1.162                                                                             5)                                                                              .000                                      R 1.000                                                                             ANG                                                                              9.204                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              1.761                                                                             5)                                                                              .000                                      R .800                                                                              ANG                                                                              10.000                                                                            1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              2.275                                                                             5)                                                                              .000                                      __________________________________________________________________________     Condition Corresponding Values: γ.sub.xR /γ.sub.xO = 1.08,        γ.sub.aR /γ.sub.aO = 18.73                                   

                                      TABLE 5                                     __________________________________________________________________________    Amount DX (mm) of Movement for Focusing in Direction of Optical Axis          at Telephoto End (126.0 mm) in Comparative Embodiment                         R .000                                                                              ANG                                                                              .000                                                                              1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                              4)                                                                              .000                                                                              5)                                                                              .000                                     R 10.000                                                                            ANG                                                                              2.777                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                              4)                                                                              -.452                                                                             5)                                                                              .000                                     R 5.000                                                                             ANG                                                                              4.296                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                              4)                                                                              -.913                                                                             5)                                                                              .000                                     R 3.000                                                                             ANG                                                                              5.668                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                              4)                                                                              -1.542                                                                            5)                                                                              .000                                     R 2.000                                                                             ANG                                                                              6.875                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                              4)                                                                              -2.352                                                                            5)                                                                              .000                                     R 1.500                                                                             ANG                                                                              7.804                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                              4)                                                                              -3.190                                                                            5)                                                                              .000                                     R 1.000                                                                             ANG                                                                              9.185                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                              4)                                                                              -4.956                                                                            5)                                                                              .000                                     R .800                                                                              ANG                                                                              10.000                                                                            1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                              4)                                                                              -6.366                                                                            5)                                                                              .000                                     Imaging Magnification β.sub.K of Lens Units                              at Telephoto End (126.0 mm) in Comparative Embodiment                         R .000                                                                              ANG                                                                              .000                                                                              1)                                                                              -.000                                                                            2)                                                                              -.710                                                                            3)                                                                              -.890                                                                             4)                                                                              -2.626                                                                            5)                                                                              -.775                                    R 10.000                                                                            ANG                                                                              2.777                                                                             1)                                                                              -.010                                                                            2)                                                                              -.686                                                                            3)                                                                              -.908                                                                             4)                                                                              -2.649                                                                            5)                                                                              -.775                                    R 5.000                                                                             ANG                                                                              4.296                                                                             1)                                                                              -.021                                                                            2)                                                                              -.663                                                                            3)                                                                              -.927                                                                             4)                                                                              -2.673                                                                            5)                                                                              -.775                                    R 3.000                                                                             ANG                                                                              5.668                                                                             1)                                                                              -.036                                                                            2)                                                                              -.632                                                                            3)                                                                              -.952                                                                             4)                                                                              -2.705                                                                            5)                                                                              -.775                                    R 2.000                                                                             ANG                                                                              6.875                                                                             1)                                                                              -.056                                                                            2)                                                                              -.595                                                                            3)                                                                              -.985                                                                             4)                                                                              -2.746                                                                            5)                                                                              -.775                                    R 1.500                                                                             ANG                                                                              7.804                                                                             1)                                                                              -.078                                                                            2)                                                                              -.559                                                                            3)                                                                              -1.019                                                                            4)                                                                              -2.789                                                                            5)                                                                              -.775                                    R 1.000                                                                             ANG                                                                              9.185                                                                             1)                                                                              -.130                                                                            2)                                                                              -.491                                                                            3)                                                                              -1.092                                                                            4)                                                                              -2.879                                                                            5)                                                                              -.775                                    R .800                                                                              ANG                                                                              10.000                                                                            1)                                                                              -.176                                                                            2)                                                                              -.442                                                                            3)                                                                              -1.150                                                                            4)                                                                              -2.951                                                                            5)                                                                              -.775                                    Conversion Coefficient γ.sub.x Associated With Direction of Optical     Axis                                                                          at Telephoto End (126.0 mm) in Comparative Embodiment                         R .000                                                                              ANG                                                                              .000                                                                              1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                              4)                                                                              -3.543                                                                            5)                                                                              .000                                     R 10.000                                                                            ANG                                                                              2.777                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                              4)                                                                              -3.617                                                                            5)                                                                              .000                                     R 5.000                                                                             ANG                                                                              4.296                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                              4)                                                                              -3.692                                                                            5)                                                                              .000                                     R 3.000                                                                             ANG                                                                              5.668                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                              4)                                                                              -3.795                                                                            5)                                                                              .000                                     R 2.000                                                                             ANG                                                                              6.875                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                              4)                                                                              -3.931                                                                            5)                                                                              .000                                     R 1.500                                                                             ANG                                                                              7.804                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                              4)                                                                              -4.073                                                                            5)                                                                              .000                                     R 1.000                                                                             ANG                                                                              9.185                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                              4)                                                                              -4.380                                                                            5)                                                                              .000                                     R .800                                                                              ANG                                                                              10.000                                                                            1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                              4)                                                                              -4.632                                                                            5)                                                                              .000                                     Slope dx/da of Focus Cam                                                      at Telephoto End (126.0 mm) in Comparative Embodiment                         R .000                                                                              ANG                                                                              .000                                                                              1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                              4)                                                                              -.109                                                                             5)                                                                              .000                                     R 10.000                                                                            ANG                                                                              2.777                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                              4)                                                                              -.241                                                                             5)                                                                              .000                                     R 5.000                                                                             ANG                                                                              4.296                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                              4)                                                                              -.373                                                                             5)                                                                              .000                                     R 3.000                                                                             ANG                                                                              5.668                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                              4)                                                                              -.560                                                                             5)                                                                              .000                                     R 2.000                                                                             ANG                                                                              6.875                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                              4)                                                                              -.791                                                                             5)                                                                              .000                                     R 1.500                                                                             ANG                                                                              7.804                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                              4)                                                                              -1.024                                                                            5)                                                                              .000                                     R 1.000                                                                             ANG                                                                              9.185                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                              4)                                                                              -1.588                                                                            5)                                                                              .000                                     R .800                                                                              ANG                                                                              10.000                                                                            1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                              4)                                                                              -1.802                                                                            5)                                                                              .000                                     Conversion Coefficient γ.sub.a Associated With Direction of             Rotation                                                                      at Telephoto End (126.0 mm) in Comparative Embodiment                         R .000                                                                              ANG                                                                              .000                                                                              1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                              4)                                                                              .385                                                                              5)                                                                              .000                                     R 10.000                                                                            ANG                                                                              2.777                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                              4)                                                                              .871                                                                              5)                                                                              .000                                     R 5.000                                                                             ANG                                                                              4.296                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                              4)                                                                              1.378                                                                             5)                                                                              .000                                     R 3.000                                                                             ANG                                                                              5.668                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                              4)                                                                              2.124                                                                             5)                                                                              .000                                     R 2.000                                                                             ANG                                                                              6.875                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                              4)                                                                              3.107                                                                             5)                                                                              .000                                     R 1.500                                                                             ANG                                                                              7.804                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                              4)                                                                              4.172                                                                             5)                                                                              .000                                     R 1.000                                                                             ANG                                                                              9.185                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                              4)                                                                              6.955                                                                             5)                                                                              .000                                     R .800                                                                              ANG                                                                              10.000                                                                            1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                              4)                                                                              8.348                                                                             5)                                                                              .000                                     __________________________________________________________________________     Condition Corresponding Values: γ.sub.xR /γ.sub.xO = 1.31,        γ.sub.aR /γ.sub.aO = 21.70                                   

As can be seen from Tables 3, 4, and 5, the value of the conversioncoefficient γ_(x) associated with the direction of the optical axis andthe slope (dx/da) of the focus cam at the respective focal lengthsincrease as the photographing distance becomes closer to the closestdistance. Therefore, as can be seen from these tables, the conversioncoefficient γ_(a) associated with the direction of rotation, which isdefined as the product of γ_(x) and (dx/da), further increases.

More specifically, in a zoom lens in which the conversion coefficientγ_(x) associated with the amount x of movement, in the direction of theoptical axis, of the focusing lens unit in a closest in-focus state islarger than that in an infinity in-focus state, i.e., which satisfies:

    1.0<γ.sub.xR /γ.sub.x0

when the focus cam which satisfies the following inequality, i.e., thefocus cam has a shape having a larger slope (dx/da) at the closestcorresponding position than that at the infinity corresponding position:

    1.0<<(dx/da).sub.R /(dx/da).sub.0

the following inequality is satisfied:

    1.0<γ.sub.xR /γ.sub.x0 <<γ.sub.aR /γ.sub.a0

The rate of change, from the infinity in-focus value (Y_(a0)) to theclosest in-focus value (γ_(aR)), of the conversion coefficient γ_(a)associated with the angle a of rotation of the rotatable lens barrelundesirably becomes larger than the rate of change, from the infinityin-focus value (γ_(x0)) to the closest in-focus value (γ_(xR)), of theconversion coefficient γ_(x) associated with the amount x of movement inthe direction of the optical axis.

From Tables 3, 4, and 5 above, the rate of change of γ_(a) is ×14.24 atthe wide-angle end (F=28.8), ×18.73 at the middle position (F=70.0), and×21.70 at the telephoto-end (F=126.0).

As described above, when the conversion coefficient γ changes incorrespondence with the lens arrangement (e.g., focusing), as describedin Japanese Patent Application Laid-Open No. 3-228006, a plurality ofpairs of data of the conversion coefficient γ and the correctioncoefficient ε must be stored in the storage means in units of aplurality of divided focus ranges. Therefore, when the rate of change ofγ_(a) is large (γ_(aR) /γ_(a0) >>1.0), the number of divisionsincreases, and the storage capacity inevitably becomes large, resultingin an increase in cost. For example, when a change in γ_(a) in a singlefocus range is divided under the condition defined by the followinginequality:

    γ.sub.max /γ.sub.min <1.2

the number N of divisions is expressed by inequality (a) below:

    N>log(γ.sub.MAX /γ.sub.MIN)/log(1.2)           (a)

Therefore, the numbers N_(W), N_(M), and N_(T) of divisions at thewide-angle end, middle position, and telephoto end have large values asfollows:

    N.sub.W >14.6 N.sub.M >16.1 N.sub.T >16.9

The formula K=γ(1+ε·ΔBf) presented by Japanese Patent ApplicationLaid-Open No. 62-170924 is rewritten to the conversion coefficient K_(a)associated with the angle a of rotation of the rotatable lens barrel:

    K.sub.a =γ.sub.a (1+ε·ΔBf)

Then, the following formula is defined by using a correction coefficientμ (ε=-1/μ):

    K.sub.a =γ.sub.a (1-ΔBf/μ)

Tables 6, 7, and 8 below summarize the calculation results of the valuesof the conversion coefficient K_(a) and the correction coefficient μaccording to the comparative embodiment at the wide-angle end (F=28.8),middle position (F=70.0), and telephoto end (F=126.0) using the aboveformula.

In these tables, (R) is the object distance (m), (ANG) is the amount ofrotation for focusing from the infinity corresponding position on thefocus cam, (r) is the conversion coefficient γ_(a) in the direction ofrotation, (rs) is the conversion coefficient K_(a), (bf) is the defocusamount (mm), and (Λ) is the correction coefficient μ. Each table has amatrix structure, and eight rows in the vertical direction indicated by(POS) represent the object positions (R=10.0, 5.0, 3.0, 2.0, 1.5, 1.0,and 0.8 m), and four pairs (R, ANGLE) in the horizontal directionrepresent the lens arrangements of the focusing lens unit.

More specifically, the position of the focusing lens in the first pairin the upper two tables in each of Tables 6, 7, and 8, i.e., in thethird and fourth columns is (R, ANGLE)=(0.0, 0.0), and it indicates thatthis position corresponds to the infinity corresponding position.Therefore, the third column (r) in the first table represents the valueof the conversion coefficient γ_(a) in the direction of rotation whenthe focusing lens unit is focused on an infinity object, and the fourthcolumn (rs) represents the value of the conversion coefficient K_(a)when the focusing lens unit is moved from an in-focus state on aninfinity object to an in-focus state at the object distance in thesecond column. Furthermore, the third column (bf) in the second tablerepresents the defocus amount ΔBf from a predetermined imaging positionwhen the position of the focusing lens unit corresponds to the infinitycorresponding position, and the object is located at an object distancein the second column, and the fourth column (Λ) represents the value ofthe correction coefficient μ when the focusing lens unit is moved froman in-focus state on an infinity object to an in-focus state at theobject distance in the second column.

Similarly, the position of the focusing lens in the fourth pair in thelower two tables in each of Tables 6, 7, and 8, i.e., in the ninth andtenth columns is (R, ANGLE)=(0.80, 10.0), and it indicates that thisposition corresponds to the closest in-focus (R=0.80 m) correspondingposition. Therefore, the ninth column (r) in the third table representsthe value of the conversion coefficient γ_(a) in the direction ofrotation when the focusing lens unit is focused on a closest distance(R=0.80 m) object, and the tenth column (rs) represents the value of theconversion coefficient K_(a) when the focusing lens unit is moved froman in-focus state on the closest distance (R=0.80 m) object to anin-focus state at the object distance in the second column. Furthermore,the ninth column (bf) in the fourth table represents the defocus amountΔBf from a predetermined imaging position when the position of thefocusing lens unit corresponds to the closest corresponding position,and the object is located at an object distance in the second column,and the tenth column (Λ) represents the value of the correctioncoefficient μ when the focusing lens unit is moved from an in-focusstate on the closest distance (R=0.80 m) object to an in-focus state atthe object distance in the second column.

From the above formulas, since the conversion coefficient in thedirection of rotation is calculated by K_(a) =ΔBf/Δa (where Δa: theamount of rotation for focusing), and the correction coefficient μ iscalculated by μ=ΔBf/(1-K_(a) /γ_(a)), the value of the conversioncoefficient K_(a) (eighth row, fourth column in first table: 0.118) whenthe focusing lens unit is moved from an in-focus state on the infinityobject to an in-focus state at the object distance (R=0.80 m) in Table 6is calculated by K_(a) =1.18/10.0=0.118 using ΔBf=1.18 and Δa=10.0. Onthe other hand, the value of the correction coefficient μ (eighth row,fourth column in second table: -0.31) is calculated as μ=-0.31 usingΔBf=1.18, K_(a) =0.118, and γ_(a) =0.025.

                                      TABLE 6                                     __________________________________________________________________________    Conversion Coefficients K.sub.a : (rs), γ.sub.a : (r) Associated        with Direction of Rotation                                                    and Correction Coefficient μ: (l) at Wide-angle End (28.8 mm) of           Comparative Embodiment                                                        f = 28.8 mm                                                                   __________________________________________________________________________           (R,ANGLE) =                                                                   .000                                                                             .000 10.000                                                                            2.729                                                                            5.000                                                                              4.296                                                                             3.000                                                                             5.668                                      POS                                                                              R   r  rs   r   rs r    rs  r   rs                                         __________________________________________________________________________    1  .000                                                                              .025                                                                             .000     .031    .039    .050                                       2  10.000 .031 .042                                                                              .000    .055    .069                                       3  5.000  .039     .055                                                                             .069 .000    .085                                       4  3.000  .050     .069    .085                                                                              .104                                                                              .000                                       5  2.000  .063     .085    .104    .125                                       6  1.500  .076     .100    .120    .143                                       7  1.000  .100     .129    .153    .180                                       8  .800   .118     .151    .177    .207                                       __________________________________________________________________________    POS                                                                              R   bf l    bf  l  bf   l   bf  l                                          __________________________________________________________________________    1  .000                                                                              .00                                                                              .00  -.08                                                                              -.30                                                                             -.17 -.40                                                                              -.29                                                                              -.56                                       2  10.000                                                                            .08                                                                              -.35 .00 .00                                                                              -.09 -.42                                                                              -.20                                                                              -.60                                       3  5.000                                                                             .17                                                                              -.29 .09 -.30                                                                             .00  .00 -.12                                                                              -.64                                       4  3.000                                                                             .29                                                                              -.28 .20 -.33                                                                             .12  -.48                                                                              .00 .00                                        5  2.000                                                                             .44                                                                              -.28 .35 -.35                                                                             .27  -.52                                                                              .15 -.77                                       6  1.500                                                                             .59                                                                              -.29 .51 -.37                                                                             .42  -.56                                                                              .31 -.82                                       7  1.000                                                                             .92                                                                              -.30 .84 -.41                                                                             .75  -.61                                                                              .63 -.87                                       8  .800                                                                              1.18                                                                             -.31 1.10                                                                              -.43                                                                             1.01 -.64                                                                              .90 -.91                                       __________________________________________________________________________           (R,ANGLE) =                                                                   2.000                                                                            6.875                                                                              1.500                                                                             7.804                                                                            1.000                                                                              9.185                                                                             .800                                                                              10.000                                     POS                                                                              R   r  rs   r   rs r    rs  r   rs                                         __________________________________________________________________________    1  .000   .064     .076    .100    .119                                       2  10.000 .085     .100    .130    .152                                       3  5.000  .104     .121    .154    .178                                       4  3.000  .125     .143    .181    .207                                       5  2.000                                                                             .146                                                                             .000     .168    .210    .239                                       6  1.500  .167 .192                                                                              .000    .238    .269                                       7  1.000  .209     .238                                                                             .290 .000    .322                                       8  .800   .239     .269    .322                                                                              .353                                                                              .000                                       __________________________________________________________________________    POS                                                                              R   bf l    bf  l  bf   l   bf  l                                          __________________________________________________________________________    1  .000                                                                              -.44                                                                             -.77 -.59                                                                              -.98                                                                             -.92 -1.41                                                                             -1.19                                                                             -1.79                                      2  10.000                                                                            -.35                                                                             -.84 -.51                                                                              -1.07                                                                            -.84 -1.52                                                                             -1.10                                                                             -1.93                                      3  5.000                                                                             -.27                                                                             -.91 -.42                                                                              -1.14                                                                            -.75 -1.61                                                                             -1.02                                                                             -2.05                                      4  3.000                                                                             -.15                                                                             -1.01                                                                              -.31                                                                              -1.21                                                                            -.64 -1.69                                                                             -.90                                                                              -2.18                                      5  2.000                                                                             .00                                                                              .00  -.16                                                                              -1.24                                                                            -.48 -1.76                                                                             -.75                                                                              -2.32                                      6  1.500                                                                             .16                                                                              -1.08                                                                              .00 .00                                                                              -.33 -1.85                                                                             -.59                                                                              -2.50                                      7  1.000                                                                             .48                                                                              -1.13                                                                              .33 -1.37                                                                            .00  .00 -.26                                                                              -3.02                                      8  .800                                                                              .75                                                                              -1.19                                                                              .59 -1.47                                                                            .26  -2.35                                                                             .00 .00                                        __________________________________________________________________________     Condition Corresponding Values: K.sub.aO /γ.sub.aO = 4.76, K.sub.aR     /γ.sub.aR = 0.34                                                   

                                      TABLE 7                                     __________________________________________________________________________    Conversion Coefficients K.sub.a : (rs), γ.sub.a : (r) Associated        with Direction of Rotation                                                    and Correction Coefficient μ: (l) at Middle Position (70.0 mm) of          Comparative Embodiment                                                        f = 70.0 mm                                                                   __________________________________________________________________________           (R,ANGLE) =                                                                   .000                                                                             .000 10.000                                                                            2.704                                                                            5.000                                                                              4.237                                                                             3.000                                                                             5.671                                      POS                                                                              R   r  rs   r   rs r    rs  r   rs                                         __________________________________________________________________________    1  .000                                                                              .122                                                                             .000     .183    .237    .300                                       2  10.000 .183 .267                                                                              .000    .331    .405                                       3  5.000  .236     .330                                                                             .394 .000    .484                                       4  3.000  .298     .404    .483                                                                              .596                                                                              .000                                       5  2.000  .374     .498    .596    .728                                       6  1.500  .448     .589    .702    .849                                       7  1.000  .593     .765    .902    1.074                                      8  .800   .702     .897    1.050   1.242                                      __________________________________________________________________________    POS                                                                              R   bf l    bf  l  bf   l   bf  l                                          __________________________________________________________________________    1  .000                                                                              .00                                                                              .00  -.50                                                                              -1.58                                                                            -1.00                                                                              -2.52                                                                             -1.70                                                                             -3.42                                      2  10.000                                                                            .50                                                                              -.98 .00 .00                                                                              -.51 -3.16                                                                             -1.20                                                                             -3.76                                      3  5.000                                                                             1.00                                                                             -1.06                                                                              .51 -2.13                                                                            .00  .00 -.69                                                                              -3.70                                      4  3.000                                                                             1.69                                                                             -1.16                                                                              1.20                                                                              -2.34                                                                            .69  -3.06                                                                             .00 .00                                        5  2.000                                                                             2.58                                                                             -1.24                                                                              2.09                                                                              -2.41                                                                            1.59 -3.10                                                                             .90 -4.05                                      6  1.500                                                                             3.51                                                                             -1.30                                                                              3.02                                                                              -2.50                                                                            2.52 -3.22                                                                             1.83                                                                              -4.30                                      7  1.000                                                                             5.46                                                                             -1.41                                                                              4.97                                                                              -2.66                                                                            4.48 -3.48                                                                             3.80                                                                              -4.73                                      8  .800                                                                              7.02                                                                             -1.47                                                                              6.54                                                                              -2.77                                                                            6.05 -3.64                                                                             5.37                                                                              -4.96                                      __________________________________________________________________________           (R,ANGLE) =                                                                   2.000                                                                            6.903                                                                              1.500                                                                             7.822                                                                            1.000                                                                              9.204                                                                             .800                                                                              10.000                                     POS                                                                              R   r  rs   r   rs r    rs  r   rs                                         __________________________________________________________________________    1  .000   .377     .452    .600    .711                                       2  10.000 .501     .594    .773    .907                                       3  5.000  .598     .706    .909    1.060                                      4  3.000  .730     .853    1.081   1.251                                      5  2.000                                                                             .879                                                                             .000     1.016   1.269   1.458                                      6  1.500  1.014                                                                              1.162                                                                             .000    1.435   1.644                                      7  1.000  1.263    1.432                                                                            1.762                                                                              .000    2.008                                      8  .800   1.450    1.639   2.007                                                                             2.275                                                                             .000                                       __________________________________________________________________________    POS                                                                              R   bf l    bf  l  bf   l   bf  l                                          __________________________________________________________________________    1  .000                                                                              -2.60                                                                            -4.55                                                                              -3.54                                                                             -5.79                                                                            -5.52                                                                              -8.38                                                                             -7.11                                                                             -10.35                                     2  10.000                                                                            -2.10                                                                            -4.89                                                                              -3.04                                                                             -6.22                                                                            -5.03                                                                              -8.96                                                                             -6.62                                                                             -11.00                                     3  5.000                                                                             -1.59                                                                            -4.99                                                                              -2.53                                                                             -6.45                                                                            -4.52                                                                              -9.33                                                                             -6.11                                                                             -11.44                                     4  3.000                                                                             -.90                                                                             -5.29                                                                              -1.83                                                                             -6.89                                                                            -3.82                                                                              -9.89                                                                             -5.41                                                                             -12.02                                     5  2.000                                                                             .00                                                                              .00  -.93                                                                              -7.43                                                                            -2.92                                                                              -10.42                                                                            -4.51                                                                             -12.57                                     6  1.500                                                                             .93                                                                              -6.07                                                                              .00 .00                                                                              -1.98                                                                              -10.70                                                                            -3.58                                                                             -12.91                                     7  1.000                                                                             2.91                                                                             -6.66                                                                              1.98                                                                              -8.54                                                                            .00  .00 -1.60                                                                             -13.61                                     8  .800                                                                              4.49                                                                             -6.91                                                                              3.57                                                                              -8.70                                                                            1.60 -11.50                                                                            .00 .00                                        __________________________________________________________________________     Condition Corresponding Values: K.sub.aO /γ.sub.aO = 5.78, K.sub.aR     /γ.sub.aR = 0.31                                                   

                                      TABLE 8                                     __________________________________________________________________________    Conversion Coefficients K.sub.a : (rs), γ.sub.a : (r) Associated        with Direction of Rotation                                                    and Correction Coefficient μ: (l) at Telephoto End (126.0 mm) of           Comparative Embodiment                                                        f = 126.0 mm                                                                  __________________________________________________________________________           (R,ANGLE) =                                                                   .000                                                                             .000 10.000                                                                            2.777                                                                             5.000                                                                             4.296                                                                             3.000                                                                             5.668                                      POS                                                                              R   r  rs   r   rs  r   rs  r   rs                                         __________________________________________________________________________    1  .000                                                                              .385                                                                             .000     .584    .771    .999                                       2  10.000 .582 .871                                                                              .000    1.110   1.398                                      3  5.000  .765     1.107                                                                             1.379                                                                             .000    1.717                                      4  3.000  .991     1.392   1.714                                                                             2.125                                                                             .000                                       5  2.000  1.264    1.738   2.121   2.592                                      6  1.500  1.533    2.075   2.509   3.035                                      7  1.000  2.090    2.772   3.317   3.976                                      8  .800   2.531    3.322   3.953   4.715                                      __________________________________________________________________________    POS                                                                              R   bf l    bf  l   bf  l   bf  l                                          __________________________________________________________________________    1  .000                                                                              .00                                                                              .00  -1.62                                                                             -4.93                                                                             -3.31                                                                             -7.51                                                                             -5.66                                                                             -10.69                                     2  10.000                                                                            1.62                                                                             -3.16                                                                              .00 .00 -1.69                                                                             -8.66                                                                             -4.04                                                                             -11.81                                     3  5.000                                                                             3.29                                                                             -3.33                                                                              1.68                                                                              -6.19                                                                             .00 .00 -2.35                                                                             -12.25                                     4  3.000                                                                             5.62                                                                             -3.57                                                                              4.02                                                                              -6.72                                                                             2.35                                                                              -9.66                                                                             .00 .00                                        5  2.000                                                                             8.69                                                                             -3.81                                                                              7.12                                                                              -7.15                                                                             5.47                                                                              -10.16                                                                            3.13                                                                              -14.24                                     6  1.500                                                                             11.96                                                                            -4.01                                                                              10.43                                                                             -7.54                                                                             8.80                                                                              -10.74                                                                            6.48                                                                              -15.15                                     7  1.000                                                                             19.19                                                                            -4.33                                                                              17.76                                                                             -8.13                                                                             16.22                                                                             -11.53                                                                            13.98                                                                             -16.06                                     8  .800                                                                              25.31                                                                            -4.54                                                                              23.99                                                                             -8.52                                                                             22.55                                                                             -12.08                                                                            20.43                                                                             -16.76                                     __________________________________________________________________________           (R,ANGLE) =                                                                   2.000                                                                            6.875                                                                              1.500                                                                             7.804                                                                             1.000                                                                             9.185                                                                             .800                                                                              10.000                                     POS                                                                              R   r  rs   r   rs  r   rs  r   rs                                         __________________________________________________________________________    1  .000   1.272    1.533   2.034   2.379                                      2  10.000 1.742    2.066   2.683   3.103                                      3  5.000  2.119    2.491   3.200   3.676                                      4  3.000  2.587    3.008   3.825   4.367                                      5  2.000                                                                             3.107                                                                            .000     3.590   4.551   5.172                                      6  1.500  3.616                                                                              4.178                                                                             .000    5.298   5.989                                      7  1.000  4.726    5.467                                                                             6.953                                                                             .000    7.616                                      8  .800   5.586    6.435   7.943                                                                             8.360                                                                             .000                                       __________________________________________________________________________    POS                                                                              R   bf l    bf  l   bf  l   bf  l                                          __________________________________________________________________________    1  .000                                                                              -8.75                                                                            -14.81                                                                             -11.97                                                                            -18.90                                                                            -18.68                                                                            -26.40                                                                            -23.79                                                                            -33.26                                     2  10.000                                                                            -7.14                                                                            -16.25                                                                             -10.39                                                                            -20.55                                                                            -17.19                                                                            -28.00                                                                            -22.41                                                                            -35.64                                     3  5.000                                                                             -5.46                                                                            -17.19                                                                             -8.74                                                                             -21.64                                                                            -15.64                                                                            -28.97                                                                            -20.96                                                                            -37.42                                     4  3.000                                                                             -3.12                                                                            -18.64                                                                             -6.43                                                                             -22.95                                                                            -13.45                                                                            -29.91                                                                            -18.92                                                                            -39.62                                     5  2.000                                                                             .00                                                                              .00  -3.34                                                                             -23.74                                                                            -10.51                                                                            -30.43                                                                            -16.16                                                                            -42.38                                     6  1.500                                                                             3.36                                                                             -20.51                                                                             .00 .00 -7.31                                                                             -30.73                                                                            -13.15                                                                            -46.37                                     7  1.000                                                                             10.92                                                                            -20.95                                                                             7.55                                                                              -24.46                                                                            .00 .00 -6.21                                                                             -69.71                                     8  .800                                                                              17.46                                                                            -21.88                                                                             14.13                                                                             -26.15                                                                            6.48                                                                              -45.45                                                                            .00 .00                                        __________________________________________________________________________     Condition Corresponding Values: K.sub.aO /γ.sub.aO = 6.58, K.sub.aR     /γ.sub.aR = 0.28                                                   

As can be seen from Tables 6, 7, and 8 above, when a change inconversion coefficient K_(a) : (rs) (e.g., the fourth column in thefirst table) and a change in correction coefficient μ: (Λ) (e.g., thefourth column in the second table) at a given lens arrangement (e.g., atthe infinity in-focus arrangement) are considered, the conversioncoefficient K_(a) and the correction coefficient μ considerably changedepending on the object positions. In particular, the conversioncoefficient K_(a) has a larger value at the closest object side thanthat at the infinity object side. Since the conversion coefficient K_(a)in the direction of rotation is defined by K_(a) =ΔBf/Δa, the amount Δaof rotation for focusing at the infinity object side becomes larger thanthat at the closest object side relative to the defocus amount ΔBf.

The calculation results of the rate of change of K_(a) with respect toγ_(a) at the infinity in-focus arrangement and the closest in-focusarrangement at the wide-angle end (F=28.8), middle position (F=70.0),and telephoto end (F=126.0) in the comparative embodiment are asfollows.

    ______________________________________                                        Comparative                                                                              Infinity Arrangement                                                                         Closest Arrangement                                 Embodiment K.sub.aO /γ.sub.aO                                                                     K.sub.aR /γ.sub.aR                            ______________________________________                                        Wide-angle End                                                                           4.76           0.34                                                (F = 28.8)                                                                    Middle Position                                                                          5.78           0.31                                                (F = 70.0)                                                                    Telephoto End                                                                            6.58           0.28                                                (F = 126.0)                                                                   ______________________________________                                    

As described above, in the comparative embodiment, since the change inconversion coefficient K_(a) is large, the contribution of thecorrection term (ΔBf/μ) in K_(a) =γ_(a) (1-ΔBf/μ) becomes large, and thevalue of the correction coefficient μ becomes close to that of thedefocus amount ΔBf. In addition, the value of the correction coefficientμ largely changes depending on the object positions.

Therefore, as described in Japanese Patent Application Laid-Open No.3-228006, under the condition that only a pair of a conversioncoefficient γ_(a) value and a correction coefficient μ value are set fora given lens arrangement range (e.g., an infinity in-focus arrangementrange), if the correction coefficient μ which changes largely isrepresented by only one value, a large error is included in the value ofthe conversion coefficient K_(a) which is calculated from the conversioncoefficient γ_(a) and the correction coefficient μ. Therefore, when thelens driving amount Δa for focusing is finally calculated from thedefocus amount ΔBf using the conversion coefficient K_(a), the lensdriving amount includes an error, and an auto-focus operation cannot beaccurately performed.

For example, upon calculation of the lens driving amount Δa for focusingwith respect to a closest distance (R=0.80 m) object when the correctioncoefficient μ (which changes from -3.16 to -4.54 depending on the objectdistances) at the infinity in-focus arrangement at the telephoto end(F=126.0) is represented by the value (μ=-3.81) at the middle objectdistance (R=2.0 m), the lens driving amount Δa for focusing iscalculated as Δa=8.59 by substituting ΔBf=25.31, γ_(a) =0.385, andμ=-3.81 for Δa=ΔBf/ γ_(a) (1-ΔBf/μ)!. The actual lens driving amount forfocusing from the state of the infinity in-focus arrangement at thetelephoto end (F=126.0) to the closest distance (R=0.80 m) object isΔa=10.0 from (R, ANGLE)=(0.80, 10.0) in the upper right portion of thethird table in Table 8. Therefore, an error as large as -14.1% isproduced between the actual value and the calculated value Δa=8.59 ofthe lens driving amount for focusing.

Similarly, when the lens driving amounts upon focusing from the infinityin-focus lens arrangement to the closest distance object and uponfocusing from the closest in-focus lens arrangement to the infinityobject at the wide-angle end, middle position, and telephoto end arecalculated from Δa=ΔBf/ γ_(a) (1-ΔBf/μ)!, and errors from the actuallens driving amounts are then calculated, the following large values areobtained.

    ______________________________________                                        Comparative                                                                              Infinity Arrangement →                                                                Closest Arrangement →                        Embodiment Closest In-focus State                                                                       Infinity In-focus State                             ______________________________________                                        Wide-angle End                                                                           -8.7%          -26.3%                                              (F = 28.8)                                                                    Middle Position                                                                          -13.2%         -23.4%                                              (F = 70.0)                                                                    Telephoto End                                                                            -14.1%         -28.7%                                              (F = 126.0)                                                                   ______________________________________                                    

Note that the value of the correction coefficient μ upon focusing fromthe infinity in-focus lens arrangement to the closest distance objectadopts a value at the object distance (R=2.0 m), and the value of thecorrection coefficient μ upon focusing from the closest in-focus lensarrangement to the infinity object adopts a value at the object distance(R=3.0 m).

Finally, Table 9 summarizes the amount (ANGLE DA) of rotation forfocusing upon manual focusing using the focus cam (the middle table inTable 1) of the comparative embodiment, the amount DX (mm) of movement,in the direction of the optical axis, of the focusing lens unitcorresponding to the amount of rotation for focusing, and a displacementamount Bf (mm) of the imaging point when the amount (DX) of movement inthe direction of the optical axis is given.

The upper table in Table 9 summarizes the displacement amount (Bf) ofthe imaging point corresponding to the photographing distances (R=5.0,3.0, 2.0, 1.5, 1.0, and 0.8 m) in the respective zooming states of thefocal lengths (F=28.8, 35.0, 50.0, 70.0, 95.0, and 126.0 mm), and themiddle table summarizes the values of the amount (ANGLE DA) of rotationfor focusing required for attaining an optimal in-focus state withrespect to the respective photographing distances. The lower tablesummarizes the amounts (DX) of movement, in the direction of the opticalaxis, of the respective lens units corresponding to the amount (ANGLEDA) of rotation for focusing in association with the focal lengths andthe photographing distances. In the lower table, (F) is the focal length(mm) of the entire system, (R) is the photographing distance (m), and(DX) is the amount (mm) of movement, in the direction of the opticalaxis, of each of the first, second, third, fourth, and fifth lens unitsin turn from the right side (movement toward the object side isrepresented by a positive value).

                  TABLE 9                                                         ______________________________________                                        Displacement Amount Bf (mm) of Imaging Point and Amount DX (mm)               of movement for focusing in Comparative Embodiment                            ______________________________________                                                              0.80  1.00 1.50 2.00 3.00 5.00                                                m     m    m    m    m    m                             ______________________________________                                        F    28.800  Bf       .000  .000 .000 .000 .000 .000                          F    35.000  Bf       .000  -.013                                                                              -.017                                                                              -.009                                                                              -.007                                                                              -.003                         F    50.000  Bf       .000  .012 -.006                                                                              -.020                                                                              -.027                                                                              .015                          F    70.000  Bf       .000  .035 .021 .024 .002 -.023                         F    95.000  Bf       .000  .034 .041 .050 .023 .015                          F    126.000 Bf       .000  .000 .000 .000 .000 .000                               ANGLE   DA       10.000                                                                              9.185                                                                              7.804                                                                              6.875                                                                              5.668                                                                              4.296                         ______________________________________                                        F   28.800  DX     .000 .000 .000 -.365 .000 R   0.80 m                       F   35.000  DX     .000 .000 .000 -.533 .000 R   0.80 m                       F   50.000  DX     .000 .000 .000 -1.061                                                                              .000 R   0.80 m                       F   70.000  DX     .000 .000 .000 -2.019                                                                              .000 R   0.80 m                       F   95.000  DX     .000 .000 .000 -3.656                                                                              .000 R   0.80 m                       F   126.000 DX     .000 .000 .000 -6.366                                                                              .000 R   0.80 m                       F   28.800  DX     .000 .000 .000 -.284 .000 R   1.00 m                       F   35.000  DX     .000 .000 .000 -.420 .000 R   1.00 m                       F   50.000  DX     .000 .000 .000 -.825 .000 R   1.00 m                       F   70.000  DX     .000 .000 .000 -1.568                                                                              .000 R   1.00 m                       F   95.000  DX     .000 .000 .000 -2.848                                                                              .000 R   1.00 m                       F   126.000 DX     .000 .000 .000 -4.956                                                                              .000 R   1.00 m                       F   28.800  DX     .000 .000 .000 -.183 .000 R   1.50 m                       F   35.000  DX     .000 .000 .000 -.273 .000 R   1.50 m                       F   50.000  DX     .000 .000 .000 -.537 .000 R   1.50 m                       F   70.000  DX     .000 .000 .000 -1.015                                                                              .000 R   1.50 m                       F   95.000  DX     .000 .000 .000 -1.836                                                                              .000 R   1.50 m                       F   126.000 DX     .000 .000 .000 -3.190                                                                              .000 R   1.50 m                       F   28.800  DX     .000 .000 .000 -.135 .000 R   2.00 m                       F   35.000  DX     .000 .000 .000 -.201 .000 R   2.00 m                       F   50.000  DX     .000 .000 .000 -.401 .000 R   2.00 m                       F   70.000  DX     .000 .000 .000 -.747 .000 R   2.00 m                       F   95.000  DX     .000 .000 .000 -1.351                                                                              .000 R   2.00 m                       F   126.000 DX     .000 .000 .000 -2.352                                                                              .000 R   2.00 m                       F   28.800  DX     .000 .000 .000 -.089 .000 R   3.00 m                       F   35.000  DX     .000 .000 .000 -.132 .000 R   3.00 m                       F   50.000  DX     .000 .000 .000 -.268 .000 R   3.00 m                       F   70.000  DX     .000 .000 .000 -.495 .000 R   3.00 m                       F   95.000  DX     .000 .000 .000 -.890 .000 R   3.00 m                       F   126.000 DX     .000 .000 .000 -1.542                                                                              .000 R   3.00 m                       F   28.800  DX     .000 .000 .000 -.052 .000 R   5.00 m                       F   35.000  DX     .000 .000 .000 -.078 .000 R   5.00 m                       F   50.000  DX     .000 .000 .000 -.158 .000 R   5.00 m                       F   70.000  DX     .000 .000 .000 -.301 .000 R   5.00 m                       F   95.000  DX     .000 .000 .000 -.528 .000 R   5.00 m                       F   126.000 DX     .000 .000 .000 -.913 .000 R   5.00 m                       ______________________________________                                    

SUMMARY OF THE INVENTION

It is, therefore, an object of the present invention to provide a zoomlens which can suppress changes in conversion coefficient γ_(a) andcorrection coefficient μ above without making a lens barrel mechanismlarge even when the focus cam is used for achieving manual focusing, cansuppress the storage capacity by reducing the number of data of theconversion coefficient γ_(a) and correction coefficient μ to be storedin the storage means, can eliminate an error upon calculation of thelens driving amount Δa for focusing from the defocus amount ΔBf usingthe conversion coefficient K_(a), and can achieve accurateauto-focusing.

According to the present invention, in a zoom lens system in which themovement locus of a focusing lens unit is defined by synthesizing afocus cam and a zoom compensation cam so as to achieve an in-focus stateby a substantially constant amount of rotation for an identical objectdistance independently of a zooming state upon expression of apredetermined movement locus for zooming by the amount of movement, inthe direction of the optical axis, of lens units, and the angle ofrotation of a rotatable lens barrel, when the ratios (dBf/dx) of theamount dBf of infinitesimal movement of the imaging plane to the amountdx of infinitesimal movement, in the direction of the optical axis, ofthe focusing lens unit at the infinity and closest in-focus points arerespectively represented by γ_(x0) and γ_(xR), the amounts of movement,in the direction of the optical axis, of the focusing lens unit requiredfor focusing from the infinity position to the closest distance positionat the wide-angle end and the telephoto end are respectively representedby Δx_(WR) and Δx_(TR), and the amount of rotation of the focusing lensunit on the focus cam corresponding to zooming from the wide-angle endto the telephoto end and the amount of rotation corresponding tofocusing from the infinity in-focus state to the closest in-focus stateare respectively represented by a_(Z) and a_(F) the zoom lens satisfiesconditional formulas (1), (2), and (3) below at least at the telephotoend:

    1.00<γ.sub.xR /γ.sub.x0                        ( 1)

    2.00<Δx.sub.TR /Δx.sub.WR <30.00               (2)

    0.30<a.sub.F /a.sub.Z <0.80                                (3)

It is preferable that when the ratios (dBf/da) of the amount dBf ofinfinitesimal movement of the imaging plane with respect to the angle daof infinitesimal rotation of the focusing lens unit on the focus cam atthe infinity and closest in-focus points are respectively represented byγ_(a0) and γ_(aR), the zoom lens satisfies the following formula atleast at the wide-angle end and the telephoto end:

    2.00<γ.sub.aR /γ.sub.a0 <10.00.

Furthermore, it is preferable that when the conversion coefficientsK_(a), which are used when the focusing lens unit are located at thelens arrangements corresponding to the infinity and closest in-focusstates and are expressed by K_(a) =ΔBf/Δa, are respectively representedby K_(a0) and K_(aR), the zoom lens satisfies the following formulas atleast at the wide-angle end and the telephoto end:

    1.50<K.sub.a0 /γ.sub.a0 <6.00

    0.30<K.sub.aR /γ.sub.aR <0.80

where

ΔBf: the defocus amount between the imaging position of an object at anarbitrary position and a predetermined imaging point position

Δa: the angle of rotation of the focusing lens unit on the focus camrequired for attaining an in-focus state on the object.

In the present invention, since the above-mentioned conditional formulasare satisfied, even when the focus cam is used to achieve so-calledmanual focusing, changes in conversion coefficient γ_(a) and correctioncoefficient μ required for realizing accurate auto-focusing can bereduced without making a lens barrel mechanism. For this reason, thenumber of data of the conversion coefficient γ_(a) and correctioncoefficient μ to be stored in the storage means can be reduced.Furthermore, since the change in correction coefficient μ is small, anerror upon calculation of the lens driving amount Δa for focusing fromthe defocus amount ΔBf using the conversion coefficient K_(a) is small,and accurate auto-focusing can be realized.

As described above, when the zoom lens system is constituted by n lensunits, and its k-th lens unit is used as a focusing lens unit, theconversion coefficient γ_(x) associated with the direction of theoptical axis of the focusing lens unit (the ratio dBf/dx of the amountdBf of infinitesimal movement of the imaging plane to the amount dx ofinfinitesimal movement in the direction of the optical axis) isexpressed using the imaging magnifications β of the respective lensunits as follows:

    γ.sub.x =(1-β.sub.k.sup.2)β.sub.k+1.sup.2 β.sub.k+2.sup.2 . . . . β.sub.n.sup.2.

Therefore, the rate of change, from the infinity in-focus value (γ_(x0))to the closest in-focus value (γ_(xR)), of the conversion coefficientγ_(x) associated with the direction of the optical axis can be expressedusing the imaging magnifications β_(0k) and β_(Rk) of the focusing lensunit at the infinity and closest in-focus points as follows:

    γ.sub.xR /γ.sub.x0 =(1-β.sub.Rk.sup.2)/(1-β.sub.0k.sup.2)

On the other hand, the conversion coefficient γ_(a) associated with thedirection of rotation of the focusing lens unit (the ratio dBf/da of theamount dBf of infinitesimal movement of the imaging plane to the angleda of infinitesimal rotation) can be expressed by:

    γ.sub.a =γ.sub.x ·(dx/da)

where dx/da is the slope of the focus cam. For this reason, the rate ofchange, from the infinity in-focus value (γ_(a0)) to the closestin-focus value (γ_(aR)), of the conversion coefficient γ_(a) associatedwith the direction of rotation of the focusing lens unit can beexpressed using slopes (dx/da)₀ and (dx/da)_(R) at the infinity andclosest corresponding positions on the focus cam as follows:

    γ.sub.aR /γ.sub.a0 =(γ.sub.xR /γ.sub.x0)·((dx/da).sub.R /(dx/da).sub.0).

Therefore, like in the present invention, in the zoom lens system inwhich the value of the conversion coefficient γ_(x) associated with theamount x of movement, in the direction of the optical axis, of thefocusing lens unit in the closest in-focus state becomes larger thanthat in the infinity in-focus state (1.0<γ_(xR) /γ_(x0)), the ratio ofthe amount a_(F) of rotation of the focusing lens unit on the focus camcorresponding to focusing from the infinity in-focus state to theclosest in-focus state and the amount a_(Z) of rotation corresponding tozooming from the wide-angle end to the telephoto end is set to besmaller than 1 (a_(F) /a_(Z) <1), so that the change in the slope(dx/da) of the focus cam is reduced, thereby reducing the change inconversion coefficient γ_(a) associated with the direction of rotation.

More specifically, since the rate of change (γ_(aR) /γ_(a0)), from theinfinity in-focus value (γ_(a0)) to the closest in-focus value (γ_(aR)),of the conversion coefficient γ_(a) associated with the direction ofrotation is expressed as a product of the rate of change (γ_(xR)/γ_(x0)) of the conversion ratio γ_(x) associated with the direction ofthe optical axis and the slope ratio (dx/da)_(R) /(dx/da)₀ of the focuscam, as described above, the final rate of change (γ_(aR) /γ_(a0)) ofthe conversion coefficient γ_(a) associated with the direction ofrotation can be compressed by adopting an arrangement in which a valueof the slope ratio of the focus cam does not become too large.

According to the present invention, in a zoom lens in which theconversion coefficients γ_(x0), γ_(xR) associated with the amount x ofmovement, in the direction of the optical axis, of the focusing lensunit at the infinity and closest in-focus points at the telephoto endsatisfies conditional formula (1), and the ratio between the amountsΔx_(WR) and Δx_(TR) of movement, in the direction of the optical axis,of the focusing lens unit required for focusing from the infinityposition to the closest distance position at the wide-angle end and thetelephoto end satisfies conditional formula (2):

    1.00<γ.sub.xR /γ.sub.x0                        ( 1)

    2.00<Δx.sub.TR /Δx.sub.WR <30.00               (2)

the ratio of the amount a_(F) of rotation of the focusing lens unit onthe focus cam corresponding to focusing from the infinity in-focus stateto the closest in-focus state to the amount a_(Z) of rotationcorresponding to zooming from the wide-angle end to the telephoto end isset to satisfy conditional formula (3):

    0.30<a.sub.F /a<0.80                                       (3)

Under these conditions, the final rate of change (γ_(aR) /γ_(a0)) of theconversion coefficient γ_(a) associated with the direction of rotationcan be set to be a small value which satisfies conditional formula (4)below:

    2.00<γ.sub.aR /γ.sub.a0 <10.00                 (4)

As described above, since the change in conversion coefficient γ_(a) canbe reduced as compared to that in the conventional system, the number ofdata of the conversion coefficient γ_(a) and the correction coefficientμ to be stored in the storage means can be reduced.

For example, upon division of the focus range like in formula (a)(N>log(γ_(MAX) /γ_(MIN))/log(1.2)) above, the following relation issatisfied:

    3.8<log(γ.sub.MAX /γ.sub.MIN)/log(1.2)<12.6

and the number of divisions can be smaller than in the conventionalsystem. Therefore, cost can be reduced in terms of the storage capacity.Furthermore, as will be described later in the following description ofthe embodiments, since the changes in conversion coefficient K_(a) andcorrection coefficient μ are smaller than those in the conventionalsystem, an error obtained upon calculation of the lens driving amount Δafor focusing from the defocus amount ΔBf using the conversioncoefficient K_(a) is small, and an accurate auto-focusing operation canbe realized.

The conditional formulas of the present invention will be explainedbelow.

Conditional formula (1) is associated with the focusing lens unit in thezoom lens according to the present invention. When γ_(xR) /γ_(x0) issmaller than the lower limit of conditional formula (1) (γ_(xR) /γ_(x0)<1.0), the optimal values of the ratio between the amounts of focusingmovement of the focusing lens unit (Δx_(TR) /Δx_(WR)) and the ratiobetween the amounts of rotation thereof (a_(F) /a_(Z)) fall outsideranges defined by conditional formulae (2) and (3), respectively.

Conditional formula (2) is associated with the ratio between the amountsof movement, in the direction of the optical axis, of the focusing lensunit required for focusing from the infinity position to the closestdistance position at the wide-angle end and the telephoto end. As willbe described later in the description of the embodiments, this ratio isan amount which is associated with the ratio of the slope (dx/da)_(R) atthe closest corresponding position to the slope (dx/da)₀ at the infinitycorresponding position on the focus cam. As the ratio between the twoamounts of movement becomes smaller, changes in slope on the focus cambecome smaller. On the contrary, as the ratio between the two amounts ofmovement becomes larger, changes in slope on the focus cam becomelarger. Therefore, when the ratio is smaller than the lower limit ofconditional formula (2), changes in conversion coefficient γ_(a)associated with the direction of rotation become small. However, in thezoom lens of the present invention, which satisfies conditional formula(1), the optimal ratio of the amount a_(F) of rotation of the focusinglens unit on the focus cam corresponding to focusing from the infinityin-focus state to the closest in-focus state to the amount a_(Z) ofrotation corresponding to zooming from the wide-angle end to thetelephoto end falls outside a range defined by conditional formula (3).So, it is more preferable to set the lower limit of conditional formula(2) to 4.7. On the other hand, when the ratio exceeds the upper limit ofconditional formula (2), since changes in slope on the focus cam becometoo large as compared to those in conversion coefficient γ_(x)associated with the direction of the optical axis, changes in conversioncoefficient γ_(a) associated with the direction of rotation becomelarge, and the number of data of the conversion coefficient γ_(a) andthe correction coefficient μ to be stored in the storage meansincreases. In addition, an accurate auto-focusing operation cannot beperformed. So, it is more preferable to set the upper limit ofconditional formula (2) to 20.0.

Conditional formula (3) defines an appropriate ratio of the amount a_(F)of rotation of the focusing lens unit on the focus cam corresponding tofocusing from the infinity in-focus state to the closest in-focus stateto the amount a_(Z) of rotation corresponding to zooming from thewide-angle end to the telephoto end. When the ratio exceeds the upperlimit of conditional formula (3), the value of the slope (dx/da) of thefocus cam considerably increases at the closest corresponding positionas compared to the slope at the infinity corresponding position, andthey have a ratio:

    1.0<<(dx/da).sub.R /(dx/da).sub.0

For this reason, the rate of change of the conversion coefficient γ_(a)associated with the direction of rotation, which rate is expressed as aproduct of the rate of change (γ_(xR) /γ_(x0)) of the conversioncoefficient γ_(x) associated with the direction of the optical axis andthe slope ratio ((dx/da)_(R) /(dx/da)₀) of the focus cam, becomesexcessively larger than 1.0 (1.0<<γ_(aR) /γ_(a0)). As a result, thenumber of data of the conversion coefficient γ_(a) and the correctioncoefficient μ to be stored in the storage means increases. In addition,since changes in μ are large, an error obtained upon calculation of thelens driving amount Δa from the defocus amount ΔBf is large, and anaccurate auto-focusing operation cannot be performed.

On the contrary, when the ratio becomes smaller than the lower limit ofconditional formula (3), since the rate of change (γ_(aR) /γ_(a0)) ofthe conversion coefficient γ_(a) becomes closer to 1.0, changes in γ_(a)become small, and the number of data of the conversion coefficient γ_(a)and the correction coefficient μ to be stored in the storage means canbe reduced. However, the slope (dx/da)₀ of the focus cam at the closestcorresponding position at the telephoto end becomes large. In this case,in order to perform a smooth focusing operation in a lens barrelmechanism in which a focus cam has a small angle of slope, the diameterof a cam cylinder corresponding to the focus cam is required to belarge, so that it becomes impossible to keep the size of the lens barrelto be small. So, it is more preferable to set the lower limit of theformula (3) to 0.50.

Conditional formula (4) is a condition associated with the number ofdata of the conversion coefficient γ_(a) and the correction coefficientμ to be stored in the storage means, i.e., the number of divisions ofthe focus range. When γ_(aR) /γ_(a0) exceeds the upper limit ofconditional formula (4), the rate of change (γ_(aR) /γ_(a0)) of theconversion coefficient γ_(a) becomes excessively large than 1.0, andchanges in γ_(a) become large. As a result, since the number of data ofthe conversion coefficient γ_(a) and the correction coefficient μ to bestored in the storage means increases, a storage means with a largestorage capacity is required, resulting in an increase in cost.

On the contrary, when γ_(aR) /γ_(a0) is smaller than the lower limit ofconditional formula (4), since the rate of change (γ_(aR) /γ_(a0)) ofthe conversion coefficient γ_(a) becomes closer to 1.0, changes in γ_(a)become small, and the number of data of the conversion coefficient γ_(a)and the correction coefficient μ to be stored in the storage means canbe reduced. However, since the conversion coefficient γ_(a) must have aconsiderably large value, the sensitivity (dBf/da) associated with themovement in the direction of rotation becomes strict, and a change inimaging point caused by a slight error factor in the direction ofrotation becomes large, thus disturbing accurate auto-focusing.

Furthermore, in order to attain accurate auto-focusing while loweringthe sensitivity (dBf/da) associated with the movement in the directionof rotation, the upper and lower limits of conditional formula (4) arepreferably set as follows:

    3.00<γ.sub.aR /γ.sub.a0 <8.00

In order to obtain a zoom lens which can perform auto-focusing moreaccurately, when the conversion coefficients K_(a) (=ΔBf/Δa) used whenthe focusing lens unit is located at the lens arrangements correspondingto the infinity in-focus state and the closest in-focus state arerespectively represented by K_(a0) and K_(aR), the zoom lens preferablysatisfies conditional formulas (5) and (6) below at least at thewide-angle end and the telephoto end:

    1.50<K.sub.a0 /γ.sub.a0 <6.00                        (5)

    0.30<K.sub.aR /γ.sub.aR <0.80                        (6)

Conditional formula (5) defines the rate of change of the conversioncoefficient K_(a) in the direction of rotation upon a change in objectposition when the focusing lens unit corresponds to an arrangement inthe infinity in-focus state. When the rate exceeds the upper limit ofconditional formula (5), the value of conversion coefficient K_(a0) upona change in object position becomes too large as compared to theconversion coefficient γ_(a0) as the sensitivity associated with themovement in the direction of rotation of the focusing lens unit at theinfinity in-focus point. Therefore, for example, when the conversioncoefficient K_(a0) which changes upon a change in object position isexpressed by a pair of a conversion coefficient γ_(a0) value and acorrection coefficient pao value on the basis of the relationship K_(a0)=γ_(a0) (1-ΔBf/μ_(a0)), a large error is produced in the value of theconversion coefficient K_(a0) calculated from the conversion coefficientγ_(a0) and the correction coefficient μ_(a0), thus disturbing accurateauto-focusing. So, it is more preferable to set the upper limit ofconditional formula (5) to 5.00.

On the contrary, when the rate is smaller than the lower limit ofconditional formula (5), the value of conversion coefficient K_(a0) inthe direction of rotation upon a change in object position becomes closeto the value of the conversion coefficient γ_(a0) as the sensitivityassociated with the movement in the direction of rotation of thefocusing lens unit at the infinity in-focus point, so that it becomespossible to achieve auto-focusing more accurately. However, when therate is smaller than the lower limit of conditional formula (5), theratio (a_(F) /a_(Z)) of the amount of rotation corresponding to focusingto the amount of rotation corresponding to zooming becomes smaller thanthe lower limit of conditional formula (3), so that it becomesimpossible to perform a smooth focusing operation.

Conditional formula (6) defines the rate of change of the conversioncoefficient K_(a) in the direction of rotation upon a change in objectposition when the focusing lens unit corresponds to an arrangement inthe closest in-focus position. When the rate is lower than the lowerlimit of conditional formula (6), the value of conversion coefficientK_(aR) in the direction of rotation upon a change in object positionbecomes too small as compared to the conversion coefficient γ_(aR) asthe sensitivity associated with the movement in the direction ofrotation of the focusing lens unit at the closest in-focus point.Therefore, for example, when the conversion coefficient K_(aR) whichchanges upon a change in object position is expressed by a pair of aconversion coefficient γ_(aR) value and a correction coefficient μ_(aR)value on the basis of the relationship K_(aR) =γ_(aR) (1-ΔBf/μ_(aR)), alarge error is produced in the value of the conversion coefficientK_(aR) calculated from the conversion coefficient γ_(aR) and thecorrection coefficient μ_(aR), thus disturbing accurate auto-focusing.So, it is more preferable to set the lower limit of formula (6) to 0.35.

On the contrary, when the rate exceeds the upper limit of conditionalformula (6), the value of conversion coefficient K_(a0) in the directionof rotation upon a change in object position becomes close to the valueof the conversion coefficient γ_(a0) as the sensitivity associated withthe movement in the direction of rotation of the focusing lens unit atthe infinity in-focus point, so that it becomes possible to achieveauto-focusing more accurately. However, when the rate is smaller thanthe lower limit of conditional formula (6), the ratio (a_(F) /a_(Z)) ofthe amount of rotation corresponding to focusing to the amount ofrotation corresponding to zooming becomes smaller than the lower limitof conditional formula (3), so that it becomes impossible to perform asmooth focusing operation.

The above and other objects, features and advantages of the presentinvention are explained hereinafter and may be better understood byreference to the drawings and the descriptive matter which follows.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a view showing the movement loci for zooming of a zoom lensaccording to the first embodiment of the present invention;

FIG. 1B is a view showing the shapes of a focus cam and a zoomcompensation cam of a second lens unit in the zoom lens according to thefirst embodiment of the present invention; and

FIG. 2 is a view for explaining the shape of the focus cam in the zoomlens according to the first embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention will be described in detail hereinafter withreference to its embodiments.

First Embodiment!

A zoom lens of the first embodiment is a zoom lens which has a five-unitarrangement, i.e., positive, negative, positive, negative, and positivelens units, and attains focusing by a negative second lens unit. In thiszoom lens, the rotation amount ratio (a_(F) /a_(Z)) of the rotationamount for focusing from the infinity in-focus position to the closestin-focus position (R=0.80 m) to the amount of rotation for zooming fromthe wide-angle end (F=28.8) to the telephoto end (F=126.0) is set to be0.55.

Table 10 below summarizes various paraxial data of an optical system anddata for defining the shape of a focus cam according to the firstembodiment.

The upper table in Table 10 summarizes the focal length data, and theprincipal point interval data of the respective lens units of theoptical system corresponding to the first embodiment.

In this table, F1, F2, F3, F4, and F5 are respectively the focal lengthsof first, second, third, fourth, and fifth lens units, and D1, D2, D3,D4, and D5 are respectively the principal point interval between thefirst and second lens units, the principal point interval between thesecond and third lens units, the principal point interval between thethird and fourth lens units, the principal point interval between thefourth and fifth lens units, and the principal point interval betweenthe fifth lens unit and a predetermined imaging plane in six zoomingstates (F=28.8 (1-POS), 35.0 (2-POS), 50.0 (3-POS), 70.0 (4-POS), 95.0(5-POS), and 126.0 mm (6-POS)).

The middle table in Table 10 summarizes spline sample data when theshape (a curve g_(4F) in FIG. 1B) of the focus cam in the second lensunit of the first embodiment, which is used for focusing, is expressedby the above-mentioned spline function associated with the angle a ofrotation of a rotatable lens barrel and the amount x of movement in thedirection of the optical axis. In this middle table, (1), (2), (3), (4),and (5) correspond to the first, second, third, fourth, and fifth lensunits, respectively.

Furthermore, the lower table in Table 10 summarizes the infinityfocusing positions (infinity corresponding positions) at the respectivefocal lengths (F=28.8, 35.0, 50.0, 70.0, 95.0 and 126.0 mm), and theamounts of rotation (amounts of rotation for focusing) upon focusing torespective photographing distances (R=5.0, 3.0, 2.0, 1.5, 1.0, and 0.8m) using the focus cam of the first embodiment. In the lower table inTable 10, since the amount of rotation for zooming from the wide-angleend (F=28.8) to the telephoto end (F=126.0) is set to be 10.0, and theamount of rotation for focusing from the infinity in-focus position tothe closest in-focus position (R=0.80 m) is set to be 5.5, the rotationamount ratio (a_(F) /a_(Z)) of the amount of rotation for focusing tothe amount of rotation for zooming in the first embodiment is 0.55.

                                      TABLE 10                                    __________________________________________________________________________    First Embodiment f = 28.8 to 126.0                                            (Rotation Amount Ratio: a.sub.F /a.sub.Z = 0.55)                              __________________________________________________________________________    Focal lengths and Principal Point Intervals of Lens Units of First            Embodiment                                                                               1-POS                                                                             2-POS                                                                              3-POS                                                                             4-POS                                                                              5-POS                                                                             6-POS                                        __________________________________________________________________________            F  28.8000                                                                           35.0000                                                                            50.0000                                                                           70.0000                                                                            95.0000                                                                           126.0000                                     F1 98.0000                                                                            D1 9.3696                                                                            15.5678                                                                            26.0774                                                                           35.1343                                                                            42.9607                                                                           49.3378                                      F2 -20.2000                                                                           D2 34.5121                                                                           30.5093                                                                            24.1872                                                                           19.0594                                                                            14.7856                                                                           10.6994                                      F3 21.3000                                                                            D3 8.9319                                                                            9.5307                                                                             10.6727                                                                           11.7442                                                                            12.4611                                                                           13.1911                                      F4 -19.6000                                                                           D4 14.4820                                                                           13.8832                                                                            12.7412                                                                           11.6697                                                                            10.9528                                                                           10.2228                                      F5 35.5000                                                                            D5 49.8013                                                                           51.5975                                                                            55.0237                                                                           58.2383                                                                            61.1451                                                                           63.0195                                      __________________________________________________________________________    Focus Cam Shape (Spline Interpolation Sample Point)                           Corresponding to Comparative embodiment                                             ANGLE                                                                             (1)    (2)                                                                              (3)    (4)  (5)                                           __________________________________________________________________________     1    .0000                                                                             .0000  .0000                                                                            .0000  .0000                                                                              .0000                                          2    1.5427                                                                            .0000  .0000                                                                            .0000  -.0524                                                                             .0000                                          3    2.2918                                                                            .0000  .0000                                                                            .0000  -.0886                                                                             .0000                                          4    3.0895                                                                            .0000  .0000                                                                            .0000  -.1351                                                                             .0000                                          5    3.7470                                                                            .0000  .0000                                                                            .0000  -.1832                                                                             .0000                                          6    4.8127                                                                            .0000  .0000                                                                            .0000  -.2845                                                                             .0000                                          7    5.5000                                                                            .0000  .0000                                                                            .0000  -.3653                                                                             .0000                                          8    10.0000                                                                           .0000  .0000                                                                            .0000  -1.6304                                                                            .0000                                          9    11.5427                                                                           .0000  .0000                                                                            .0000  -2.5438                                                                            .0000                                         10    12.2918                                                                           .0000  .0000                                                                            .0000  -3.1726                                                                            .0000                                         11    13.0895                                                                           .0000  .0000                                                                            .0000  -3.9825                                                                            .0000                                         12    13.7470                                                                           .0000  .0000                                                                            .0000  -4.8202                                                                            .0000                                         13    14.8127                                                                           .0000  .0000                                                                            .0000  -6.5859                                                                            .0000                                         14    15.5000                                                                           .0000  .0000                                                                            .0000  -7.9969                                                                            .0000                                         15    17.0000                                                                           .0000  .0000                                                                            .0000  -12.8000                                                                           .0000                                         __________________________________________________________________________    Amount of Rotation for Zooming and                                            Amount of Rotation for Focusing of First Embodiment                           (Rotation Amount Ratio: a.sub.F /a.sub.Z = 0.55)                                      Infinity                                                                      Corresponding                                                                          Photographing                                                                            Amount of Rotation                                Focal Length                                                                          Position Distance   for Focusing                                      __________________________________________________________________________     28.8 mm                                                                               .0000    5.00 m    1.543                                              35.0 mm                                                                               1.2900   3.00 m    2.292                                              50.0 mm                                                                               3.5900   2.00 m    3.090                                              70.0 mm                                                                               5.8700   1.50 m    3.747                                              95.0 mm                                                                               8.0500   1.00 m    4.813                                             126.0 mm                                                                              10.0000   0.80 m    5.500                                             Condition Corresponding Value (1)                                                               1.31                                                        Condition Corresponding Value (2)                                                              17.44                                                        Condition Corresponding Value (3)                                                               0.55                                                        Condition Corresponding Value (4)                                                               4.44 (wide-angle end)                                                                   6.73 (telephoto end)                              Condition Corresponding Value (5)                                                               2.23 (wide-angle end)                                                                   2.75 (telephoto end)                              Condition Corresponding Value (6)                                                               0.51 (wide-angle end)                                                                   0.38 (telephoto end)                              __________________________________________________________________________

Table 11 below summarizes the numerical value data of the cams of thefocusing lens unit in the first embodiment, which data are calculated byinterpolation based on a spline function on the basis of the sample dataof the focus cam summarized in the middle table in Table 10. In thistable, (ANGLE) is the angle of rotation of the rotatable lens barrel,(4) is the amount (mm) of movement, in the direction of the opticalaxis, of the fourth lens unit, and (F) is the focal length (mm) of theentire system in an infinity in-focus state corresponding to the amount(ANGLE) of rotation.

                  TABLE 11                                                        ______________________________________                                        Cam Numerical Value Data of Focusing Lens Unit                                in First Embodiment                                                                                 Zoom Compensation                                       Focus Cam Numerical Value Data                                                                      Cam Numerical Value Data                                ANGLE  (4)     F          ANGLE (4)     F                                     ______________________________________                                        .0000  .0000   28.8000    .0000 .0000   28.8000                               .5000  -.0150  31.0655    .5000 .4718   31.0655                               1.0000 -.0315  33.4949    1.0000                                                                              .9526   33.4949                               1.5000 -.0506  36.1420    1.5000                                                                              1.4526  36.1420                               2.0000 -.0736  39.0489    2.0000                                                                              1.9745  39.0489                               2.5000 -.0998  42.2208    2.5000                                                                              2.5076  42.2208                               3.0000 -.1293  45.6495    3.0000                                                                              3.0398  45.6495                               3.5000 -.1639  49.3165    3.5000                                                                              3.5605  49.3165                               4.0000 -.2047  53.2032    4.0000                                                                              4.0638  53.2032                               4.5000 -.2520  57.3202    4.5000                                                                              4.5619  57.3202                               5.0000 -.3050  61.6915    5.0000                                                                              5.0711  61.6915                               5.5000 -.3653  66.3481    5.5000                                                                              5.6101  66.3481                               6.0000 -.4371  71.3281    6.0000                                                                              6.2021  71.3281                               6.5000 -.5225  76.6460    6.5000                                                                              6.8465  76.6460                               7.0000 -.6231  82.2599    7.0000                                                                              7.4937  82.2599                               7.5000 -.7404  88.1528    7.5000                                                                              8.1017  88.1528                               8.0000 -.8759  94.3598    8.0000                                                                              8.6532  94.3598                               8.5000 -1.0311 100.9772   8.5000                                                                              9.1531  100.9772                              9.0000 -1.2076 108.2210   9.0000                                                                              9.6289  108.2210                              9.5000 -1.4068 116.3987   9.5000                                                                              10.1026 116.3987                              10.0000                                                                              -1.6304 126.0000   10.0000                                                                             10.5894 126.0000                              10.5000                                                                              -1.8816 .0000                                                          11.0000                                                                              -2.1712 .0000                                                          11.5000                                                                              -2.5119 .0000                                                          12.0000                                                                              -2.9130 .0000                                                          12.5000                                                                              -3.3680 .0000                                                          13.0000                                                                              -3.8822 .0000                                                          13.5000                                                                              -4.4824 .0000                                                          14.0000                                                                              -5.1982 .0000                                                          14.5000                                                                              -6.0266 .0000                                                          15.0000                                                                              -6.9341 .0000                                                          15.5000                                                                              -7.9969 .0000                                                          ______________________________________                                    

The left table in Table 11 summarizes the numerical value data of thefocus cam of the first embodiment, and the right table in Table 11summarizes the numerical value data of the zoom compensation cam of thisembodiment. A value obtained by synthesizing the amounts (4) of movementin the direction of the optical axis in the numerical value data of thefocus cam and the zoom compensation cam in the range from the amount ofrotation (ANGLE=0.0) to the amount of rotation (ANGLE=10.0) coincideswith the movement locus (a curve g₄ in FIG. 1A) of the second lens unitcalculated using the paraxial data in the upper table in Table 10.

Therefore, the zoom compensation cam (a curve g_(4H) in FIG. 1B) isdetermined by subtracting the focus cam (the curve g_(4F) in FIG. 1B)from the movement locus (the curve g₄ in FIG. 1A) upon zooming of thesecond lens unit determined by the paraxial data in the upper table inTable 10.

FIGS. 1A, 1B and 2 will be briefly described below.

FIG. 1A shows the paraxial arrangement and the movement loci uponzooming of the zoom lens according to the first embodiment, and FIG. 1Bshows the shapes of the focus cam and the zoom compensation cam of thefourth lens unit of this embodiment. Referring to FIGS. 1A and 1B, G1,G2, G3, G4, and G5 respectively represent the first, second, third,fourth, and fifth lens units, and g₁, g₂, g₃, g₄, and g₅ respectivelyrepresent the movement loci upon zooming of the first, second, third,fourth, and fifth lens units. In addition, g_(4F) and g_(4H)respectively represent the shapes of the focus cam and the zoomcompensation cam of the fourth lens unit. As described above, a shapeobtained by synthesizing the focus cam g_(4F) and the zoom compensationcam g_(4H) of the fourth lens unit coincides with the movement locus g₄of the fourth lens unit.

FIG. 2 is a view for explaining the shape of the focus cam g_(4F) of thefirst embodiment. Referring to FIG. 2, (f=28.8; R=un) and (f=28.8;R=0.80) respectively represent the in-focus positions at the infinityand the closest distance (R=0.80 m) at the wide-angle end, andcoordinate positions (x; a) on the focus cam are respectively (x; a)=(0;0) and (x; a)=(-0.365; 5.5). On the other hand, (f=126; R=un) and(f=126; R=0.80) respectively represent the in-focus positions at theinfinity and the closest distance (R=0.80 m) at the telephoto end, andcoordinate positions (x; a) on the focus cam are respectively (x;a)=(-1.630; 10) and (x; a)=(-7.997; 15.5).

Upon zooming from the wide-angle end to the telephoto end, the secondlens unit moves on the focus cam g_(4F) from the coordinate position (0;0) to the coordinate position (-1.630; 10) for an infinity object, andfrom the coordinate position (-0.365; 5.5) to the coordinate position(-7.997; 15.5) for a closest distance object. Therefore, the second lensunit moves by 10.0 in the direction of rotation (the direction of anaxis a) in both the cases. On the other hand, upon focusing from theinfinity arrangement to the closest distance object, the second lensunit moves on the focus cam g_(4F) from the coordinate position (0; 0)to the coordinate position (-0.365; 5.5) at the wide-angle end, and fromthe coordinate position (-1.630; 10) to the coordinate position (-7.997;15.5) at the telephoto end. Therefore, the second lens unit moves by 5.5in the direction of rotation (the direction of the axis a) at theseends. In contrast to this, in the direction of the optical axis (thedirection of an axis x), the second lens unit moves by -0.365 at thewide-angle end, and by -6.367 at the telephoto end.

Since the shape of the focus cam g_(4F) is determined by interpolatingthe coordinates (f=28.8; R=un), (f=28.8; R=0.80), (f=126; R=un), and(f=126; R=0.80) by the spline function, the change in slope (dx/da) ofthe focus cam g_(4F) becomes larger as the absolute value of thex-coordinate of (f=28.8; R=0.80) is smaller or as the absolute value ofthe x-coordinate of (f=126; R=0.80) is larger. More specifically, as theratio (Δx_(TR) /Δx_(WR)) between the amounts Δx_(TR) and Δx_(WR) ofmovement, in the direction of the optical axis, of the focusing lensunit required for focusing from the infinity position to the closestdistance position at the wide-angle end or telephoto end is larger, thechange in slope (dx/da) of the focus cam becomes larger.

Tables 12, 13, and 14 below summarize the amount DX (mm) of movement forfocusing, in the direction of the optical axis, of the focusing lensunit, the imaging magnifications β_(K) of the respective lens units, theconversion coefficient γ_(x) associated with the direction of theoptical axis, the slope (dx/da) of the focus cam, and the conversioncoefficient γ_(a) associated with the direction of rotation at thewide-angle end (F=28.8), the middle position (F=70.0), and the telephotoend (F=126.0) according to the first embodiment, respectively. In thesetables, (R) on the left side is the photographing distance (m), (ANG) isthe amount of rotation on the focus cam upon focusing to the respectivephotographing distances, and 1), 2), 3), 4), and 5) on the right siderespectively represent the first, second, third, fourth, and fifth lensunits. Also, in these tables, the first table summarizes the amount DX(mm) of movement for focusing in the direction of the optical axis uponfocusing to the respective photographing distances (R=10.0, 5.0, 3.0,2.0, 1.5, 1.0, and 0.8 m) (note that movement toward the object side ispositive). The second table summarizes the imaging magnifications β_(K)of the respective lens units in an in-focus state at the respectivephotographing distances (R=10.0, 5.0, 3.0, 2.0, 1.5, 1.0, and 0.8 m).The third table summarizes the conversion coefficient γ_(x) associatedwith the direction of the optical axis of the focusing lens unit in anin-focus state at the respective photographing distances (R=10.0, 5.0,3.0, 2.0, 1.5, 1.0, and 0.8 m). Furthermore, the fourth table summarizesthe slope (dx/da) of the focus cam at the positions, on the focus cam,corresponding to an in-focus state at the respective photographingdistances (R=10.0, 5.0, 3.0, 2.0, 1.5, 1.0, and 0.8 m), and the fifthtable summarizes the conversion coefficient γ_(a) associated with thedirection of rotation of the focusing lens unit in an in-focus state atthe respective photographing distances (R=10.0, 5.0, 3.0, 2.0, 1.5, 1.0,and 0.8 m).

                                      TABLE 12                                    __________________________________________________________________________    Amount DX (mm) of Movement for Focusing in Direction of Optical Axis          at Wide-angle End (28.8 mm) in First Embodiment                               R .000                                                                              ANG                                                                              .000                                                                              1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              .000                                                                              5)                                                                              .000                                      R 10.000                                                                            ANG                                                                              .840                                                                              1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              -.026                                                                             5)                                                                              .000                                      R 5.000                                                                             ANG                                                                              1.543                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              -.052                                                                             5)                                                                              .000                                      R 3.000                                                                             ANG                                                                              2.292                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              -.089                                                                             5)                                                                              .000                                      R 2.000                                                                             ANG                                                                              3.090                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              -.135                                                                             5)                                                                              .000                                      R 1.500                                                                             ANG                                                                              3.747                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              -.183                                                                             5)                                                                              .000                                      R 1.000                                                                             ANG                                                                              4.813                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              -.284                                                                             5)                                                                              .000                                      R .800                                                                              ANG                                                                              5.500                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              -.365                                                                             5)                                                                              .000                                      Imaging Magnification β.sub.K of Lens Units                              at Wide-angle End (28.8 mm) in First Embodiment                               R .000                                                                              ANG                                                                              .000                                                                              1)                                                                              .000                                                                             2)                                                                              -.295                                                                            3)                                                                              -.541                                                                            4)                                                                              -4.568                                                                            5)                                                                              -.403                                     R 10.000                                                                            ANG                                                                              .840                                                                              1)                                                                              -.010                                                                            2)                                                                              -.291                                                                            3)                                                                              -.542                                                                            4)                                                                              -4.570                                                                            5)                                                                              -.403                                     R 5.000                                                                             ANG                                                                              1.543                                                                             1)                                                                              -.020                                                                            2)                                                                              -.287                                                                            3)                                                                              -.543                                                                            4)                                                                              -4.571                                                                            5)                                                                              -.403                                     R 3.000                                                                             ANG                                                                              2.292                                                                             1)                                                                              -.035                                                                            2)                                                                              -.281                                                                            3)                                                                              -.545                                                                            4)                                                                              -4.573                                                                            5)                                                                              -.403                                     R 2.000                                                                             ANG                                                                              3.090                                                                             1)                                                                              -.055                                                                            2)                                                                              -.274                                                                            3)                                                                              -.547                                                                            4)                                                                              -4.575                                                                            5)                                                                              -.403                                     R 1.500                                                                             ANG                                                                              3.747                                                                             1)                                                                              -.076                                                                            2)                                                                              -.266                                                                            3)                                                                              -.549                                                                            4)                                                                              -4.578                                                                            5)                                                                              -.403                                     R 1.000                                                                             ANG                                                                              4.813                                                                             1)                                                                              -.125                                                                            2)                                                                              -.250                                                                            3)                                                                              -.554                                                                            4)                                                                              -4.583                                                                            5)                                                                              -.403                                     R .800                                                                              ANG                                                                              5.500                                                                             1)                                                                              -.168                                                                            2)                                                                              -.238                                                                            3)                                                                              -.557                                                                            4)                                                                              -4.587                                                                            5)                                                                              -.403                                     Conversion Coefficient γ.sub.x Associated With Direction of Optical     Axis                                                                          at Wide-angle End (28.8 mm) in First Embodiment                               R .000                                                                              ANG                                                                              .000                                                                              1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              -3.225                                                                            5)                                                                              .000                                      R 10.000                                                                            ANG                                                                              .840                                                                              1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              -3.227                                                                            5)                                                                              .000                                      R 5.000                                                                             ANG                                                                              1.543                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              -3.229                                                                            5)                                                                              .000                                      R 3.000                                                                             ANG                                                                              2.292                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              -3.231                                                                            5)                                                                              .000                                      R 2.000                                                                             ANG                                                                              3.090                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              -3.235                                                                            5)                                                                              .000                                      R 1.500                                                                             ANG                                                                              3.747                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              -3.239                                                                            5)                                                                              .000                                      R 1.000                                                                             ANG                                                                              4.813                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              -3.246                                                                            5)                                                                              .000                                      R .800                                                                              ANG                                                                              5.500                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              -3.252                                                                            5)                                                                              .000                                      Slope dx/da of Focus Cam                                                      at Wide-angle End (28.8 mm) in First Embodiment                               R .000                                                                              ANG                                                                              .000                                                                              1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              -.030                                                                             5)                                                                              .000                                      R 10.000                                                                            ANG                                                                              .840                                                                              1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              -.034                                                                             5)                                                                              .000                                      R 5.000                                                                             ANG                                                                              1.543                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              -.043                                                                             5)                                                                              .000                                      R 3.000                                                                             ANG                                                                              2.292                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              -.053                                                                             5)                                                                              .000                                      R 2.000                                                                             ANG                                                                              3.090                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              -.065                                                                             5)                                                                              .000                                      R 1.500                                                                             ANG                                                                              3.747                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              -.082                                                                             5)                                                                              .000                                      R 1.000                                                                             ANG                                                                              4.813                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              -.107                                                                             5)                                                                              .000                                      R .800                                                                              ANG                                                                              5.500                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              -.131                                                                             5)                                                                              .000                                      Conversion Coefficient γ.sub.a Associated With Direction of             Rotation                                                                      at Wide-angle End (28.8 mm) in First Embodiment                               R .000                                                                              ANG                                                                              .000                                                                              1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              .096                                                                              5)                                                                              .000                                      R 10.000                                                                            ANG                                                                              .840                                                                              1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              .108                                                                              5)                                                                              .000                                      R 5.000                                                                             ANG                                                                              1.543                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              .138                                                                              5)                                                                              .000                                      R 3.000                                                                             ANG                                                                              2.292                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              .171                                                                              5)                                                                              .000                                      R 2.000                                                                             ANG                                                                              3.090                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              .212                                                                              5)                                                                              .000                                      R 1.500                                                                             ANG                                                                              3.747                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              .264                                                                              5)                                                                              .000                                      R 1.000                                                                             ANG                                                                              4.813                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              .348                                                                              5)                                                                              .000                                      R .800                                                                              ANG                                                                              5.500                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              .426                                                                              5)                                                                              .000                                      __________________________________________________________________________     Condition Corresponding Values: γ.sub.xR /γ.sub.xO = 1.01,        γ.sub.aR /γ.sub.aO = 4.44                                    

                                      TABLE 13                                    __________________________________________________________________________    Amount DX (mm) of Movement for Focusing in Direction of Optical               Axis at Middle Position (70.0 mm) in First Embodiment                         R  .000                                                                              ANG                                                                              .000                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              .000                                                                              5)                                                                              .000                                      R  10.000                                                                            ANG                                                                              .840                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              -.146                                                                             5)                                                                              .000                                      R  5.000                                                                             ANG                                                                              1.512                                                                            1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              -.294                                                                             5)                                                                              .000                                      R  3.000                                                                             ANG                                                                              2.255                                                                            1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              -.496                                                                             5)                                                                              .000                                      R  2.000                                                                             ANG                                                                              3.033                                                                            1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              -.754                                                                             5)                                                                              .000                                      R  1.500                                                                             ANG                                                                              3.703                                                                            1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              -1.021                                                                            5)                                                                              .000                                      R  1.000                                                                             ANG                                                                              4.836                                                                            1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              -1.578                                                                            5)                                                                              .000                                      R  .800                                                                              ANG                                                                              5.526                                                                            1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              -2.019                                                                            5)                                                                              .000                                      Imaging Magnification β.sub.K of Lens Units at Middle Position (70.0     mm) in First Embodiment                                                       R  .000                                                                              ANG                                                                              .000                                                                             1)                                                                              .000                                                                             2)                                                                              -.473                                                                            3)                                                                              -.774                                                                            4)                                                                              -3.044                                                                            5)                                                                              -.641                                     R  10.000                                                                            ANG                                                                              .540                                                                             1)                                                                              -.010                                                                            2)                                                                              -.463                                                                            3)                                                                              -.780                                                                            4)                                                                              -3.051                                                                            5)                                                                              -.641                                     R  5.000                                                                             ANG                                                                              1.512                                                                            1)                                                                              -.021                                                                            2)                                                                              -.452                                                                            3)                                                                              -.786                                                                            4)                                                                              -3.059                                                                            5)                                                                              -.641                                     R  3.000                                                                             ANG                                                                              2.255                                                                            1)                                                                              -.035                                                                            2)                                                                              -.438                                                                            3)                                                                              -.795                                                                            4)                                                                              -3.069                                                                            5)                                                                              -.641                                     R  2.000                                                                             ANG                                                                              3.033                                                                            1)                                                                              -.055                                                                            2)                                                                              -.420                                                                            3)                                                                              -.806                                                                            4)                                                                              -3.082                                                                            5)                                                                              -.641                                     R  1.500                                                                             ANG                                                                              3.703                                                                            1)                                                                              -.077                                                                            2)                                                                              -.402                                                                            3)                                                                              -.817                                                                            4)                                                                              -3.096                                                                            5)                                                                              -.641                                     R  1.000                                                                             ANG                                                                              4.836                                                                            1)                                                                              -.128                                                                            2)                                                                              -.366                                                                            3)                                                                              -.840                                                                            4)                                                                              -3.124                                                                            5)                                                                              -.641                                     R  .800                                                                              ANG                                                                              5.526                                                                            1)                                                                              -.173                                                                            2)                                                                              -.339                                                                            3)                                                                              -.859                                                                            4)                                                                              -3.147                                                                            5)                                                                              -.641                                     Conversion Coefficient γ.sub.x Associated With Direction of             Optical                                                                       Axis at Middle Position (70.0 mm) in First Embodiment                         R  .000                                                                              ANG                                                                              .000                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              -3.390                                                                            5)                                                                              .000                                      R  10.000                                                                            ANG                                                                              .840                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              -3.409                                                                            5)                                                                              .000                                      R  5.000                                                                             ANG                                                                              1.512                                                                            1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              -3.428                                                                            5)                                                                              .000                                      R  3.000                                                                             ANG                                                                              2.255                                                                            1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              3.454                                                                             5)                                                                              .000                                      R  2.000                                                                             ANG                                                                              3.033                                                                            1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              -3.487                                                                            5)                                                                              .000                                      R  1.500                                                                             ANG                                                                              3.703                                                                            1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              -3.521                                                                            5)                                                                              .000                                      R  1.000                                                                             ANG                                                                              4.836                                                                            1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              -3.594                                                                            5)                                                                              .000                                      R  .800                                                                              ANG                                                                              5.526                                                                            1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              -3.652                                                                            5)                                                                              .000                                      Slope dx/da of Focus Cam at Middle Position (70.0 mm) in First                Embodiment                                                                    R  .000                                                                              ANG                                                                              .000                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              -.150                                                                             5)                                                                              .000                                      R  10.000                                                                            ANG                                                                              .840                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              -.199                                                                             5)                                                                              .000                                      R  5.000                                                                             ANG                                                                              1.512                                                                            1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              -.244                                                                             5)                                                                              .000                                      R  3.000                                                                             ANG                                                                              2.255                                                                            1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              -.300                                                                             5)                                                                              .000                                      R  2.000                                                                             ANG                                                                              3.033                                                                            1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              -.366                                                                             5)                                                                              .000                                      R  1.500                                                                             ANG                                                                              3.703                                                                            1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              -.429                                                                             5)                                                                              .000                                      R  1.000                                                                             ANG                                                                              4.836                                                                            1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              .570                                                                              5)                                                                              .000                                      R  .800                                                                              ANG                                                                              5.526                                                                            1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              -.715                                                                             5)                                                                              .000                                      Conversion Coefficient γ.sub.a Associated With Direction of             Rotation at                                                                   Middle Position (70.0 mm) in First Embodiment                                 R  .000                                                                              ANG                                                                              .000                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              .508                                                                              5)                                                                              .000                                      R  10.000                                                                            ANG                                                                              .840                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              .677                                                                              5)                                                                              .000                                      R  5.000                                                                             ANG                                                                              1.512                                                                            1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              .836                                                                              5)                                                                              .000                                      R  3.000                                                                             ANG                                                                              2.255                                                                            1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              1.037                                                                             5)                                                                              .000                                      R  2.000                                                                             ANG                                                                              3.033                                                                            1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              1.278                                                                             5)                                                                              .000                                      R  1.500                                                                             ANG                                                                              3.703                                                                            1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              1.512                                                                             5)                                                                              .000                                      R  1.000                                                                             ANG                                                                              4.836                                                                            1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              2.050                                                                             5)                                                                              .000                                      R  .800                                                                              ANG                                                                              5.526                                                                            1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              2.610                                                                             5)                                                                              .000                                      __________________________________________________________________________     Condition Corresponding Values: γ.sub.xR γ.sub.xO =               γ.sub.aR /γ.sub.aO = 5.14                                    

                                      TABLE 14                                    __________________________________________________________________________    Amount DX (mm) of Movement for Focusing in Direction of Optical Axis at       Telephoto End (126.0 mm) in First Embodiment                                  R .000                                                                              ANG                                                                              .000                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                              4)                                                                              .000                                                                              5)                                                                              .000                                      R 10.000                                                                            ANG                                                                              .855                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                              4)                                                                              -.452                                                                             5)                                                                              .000                                      R 5.000                                                                             ANG                                                                              1.543                                                                            1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                              4)                                                                              -.913                                                                             5)                                                                              .000                                      R 3.000                                                                             ANG                                                                              2.292                                                                            1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                              4)                                                                              -1.542                                                                            5)                                                                              .000                                      R 2.000                                                                             ANG                                                                              3.090                                                                            1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                              4)                                                                              -2.352                                                                            5)                                                                              .000                                      R 1.500                                                                             ANG                                                                              3.747                                                                            1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                              4)                                                                              -3.190                                                                            5)                                                                              .000                                      R 1.000                                                                             ANG                                                                              4.813                                                                            1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                              4)                                                                              -4.956                                                                            5)                                                                              .000                                      R .800                                                                              ANG                                                                              5.500                                                                            1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                              4)                                                                              -6.367                                                                            5)                                                                              .000                                      Imaging Magnification β.sub.K of Lens Units at Telephoto End (126.0      mm) in First Embodiment                                                       R .000                                                                              ANG                                                                              .000                                                                             1)                                                                              -.000                                                                            2)                                                                              -.710                                                                            3)                                                                              -.890                                                                             4)                                                                              -2.626                                                                            5)                                                                              -.775                                     R 10.000                                                                            ANG                                                                              .855                                                                             1)                                                                              -.010                                                                            2)                                                                              -.686                                                                            3)                                                                              -.908                                                                             4)                                                                              -2.649                                                                            5)                                                                              -.775                                     R 5.000                                                                             ANG                                                                              1.543                                                                            1)                                                                              -.021                                                                            2)                                                                              -.663                                                                            3)                                                                              -.927                                                                             4)                                                                              -2.673                                                                            5)                                                                              -.775                                     R 3.000                                                                             ANG                                                                              2.292                                                                            1)                                                                              -.036                                                                            2)                                                                              -.632                                                                            3)                                                                              -.952                                                                             4)                                                                              -2.705                                                                            5)                                                                              -.775                                     R 2.000                                                                             ANG                                                                              3.090                                                                            1)                                                                              -.056                                                                            2)                                                                              -.595                                                                            3)                                                                              -.985                                                                             4)                                                                              -2.746                                                                            5)                                                                              -.775                                     R 1.500                                                                             ANG                                                                              3.747                                                                            1)                                                                              -.078                                                                            2)                                                                              -.559                                                                            3)                                                                              -1.019                                                                            4)                                                                              -2.789                                                                            5)                                                                              -.775                                     R 1.000                                                                             ANG                                                                              4.813                                                                            1)                                                                              -.130                                                                            2)                                                                              -.491                                                                            3)                                                                              -1.092                                                                            4)                                                                              -2.879                                                                            5)                                                                              -.775                                     R .800                                                                              ANG                                                                              5.500                                                                            1)                                                                              -.176                                                                            2)                                                                              -.442                                                                            3)                                                                              -1.150                                                                            4)                                                                              -2.951                                                                            5)                                                                              -.775                                     Conversion Coefficient γ.sub.x Associated With Direction of Optical     Axis at                                                                       Telephoto End (126.0 mm) in First Embodiment                                  R .000                                                                              ANG                                                                              .000                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                              4)                                                                              -3.543                                                                            5)                                                                              .000                                      R 10.000                                                                            ANG                                                                              .855                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                              4)                                                                              -3.617                                                                            5)                                                                              .000                                      R 5.000                                                                             ANG                                                                              1.543                                                                            1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                              4)                                                                              -3.692                                                                            5)                                                                              .000                                      R 3.000                                                                             ANG                                                                              2.292                                                                            1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                              4)                                                                              -3.795                                                                            5)                                                                              .000                                      R 2.000                                                                             ANG                                                                              3.090                                                                            1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                              4)                                                                              -3.931                                                                            5)                                                                              .000                                      R 1.500                                                                             ANG                                                                              3.747                                                                            1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                              4)                                                                              -4.073                                                                            5)                                                                              .000                                      R 1.000                                                                             ANG                                                                              4.813                                                                            1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                              4)                                                                              -4.380                                                                            5)                                                                              .000                                      R .800                                                                              ANG                                                                              5.500                                                                            1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                              4)                                                                              -4.632                                                                            5)                                                                              .000                                      Slope dx/da of Focus Cam at Telephoto End (126.0 mm) in First Embodiment      R .000                                                                              ANG                                                                              .000                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                              4)                                                                              -.472                                                                             5)                                                                              .000                                      R 10.000                                                                            ANG                                                                              .855                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                              4)                                                                              -.598                                                                             5)                                                                              .000                                      R 5.000                                                                             ANG                                                                              1.543                                                                            1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                              4)                                                                              -.752                                                                             5)                                                                              .000                                      R 3.000                                                                             ANG                                                                              2.292                                                                            1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                              4)                                                                              -.918                                                                             5)                                                                              .000                                      R 2.000                                                                             ANG                                                                              3.090                                                                            1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                              4)                                                                              -1.136                                                                            5)                                                                              .000                                      R 1.500                                                                             ANG                                                                              3.747                                                                            1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                              4)                                                                              -1.430                                                                            5)                                                                              .000                                      R 1.000                                                                             ANG                                                                              4.813                                                                            1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                              4)                                                                              -1.827                                                                            5)                                                                              .000                                      R .800                                                                              ANG                                                                              5.500                                                                            1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                              4)                                                                              -2.431                                                                            5)                                                                              .000                                      Conversion Coefficient γ.sub.a Associated With Direction of             Rotation at                                                                   Telephoto End (126.0 mm) in First Embodiment                                  R .000                                                                              ANG                                                                              .000                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                              4)                                                                              1.674                                                                             5)                                                                              .000                                      R 10.000                                                                            ANG                                                                              .855                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                              4)                                                                              2.161                                                                             5)                                                                              .000                                      R 5.000                                                                             ANG                                                                              1.543                                                                            1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                              4)                                                                              2.775                                                                             5)                                                                              .000                                      R 3.000                                                                             ANG                                                                              2.292                                                                            1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                              4)                                                                              3.484                                                                             5)                                                                              .000                                      R 2.000                                                                             ANG                                                                              3.090                                                                            1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                              4)                                                                              4.466                                                                             5)                                                                              .000                                      R 1.500                                                                             ANG                                                                              3.747                                                                            1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                              4)                                                                              5.826                                                                             5)                                                                              .000                                      R 1.000                                                                             ANG                                                                              4.813                                                                            1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                              4)                                                                              8.003                                                                             5)                                                                              .000                                      R .800                                                                              ANG                                                                              5.500                                                                            1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                              4)                                                                              11.259                                                                            5)                                                                              .000                                      __________________________________________________________________________     Condition Corresponding Values: γ.sub.xR /γ.sub.xO = 1.31,        γ.sub.aR /γ.sub.aO = 6.73                                    

As can be seen from Tables 12, 13, and 14, at each focal length, theconversion coefficient γ_(x) associated with the direction of theoptical axis increases, and the value of the slope (dx/da) of the focuscam increases as the photographing distance becomes closer to theclosest distance. However, the degrees of change in the slope becomesmall as compared to those of what are shown in Tables 3, 4, and 5 inwhich the rotation amount ratio (a_(F) /a_(Z)) is set to be 1.0.Therefore, as can be seen from these tables, the degree of increase inthe conversion coefficient γ_(a) associated with the direction ofrotation, which is defined as the product of the conversion coefficientγ_(x) and the slope (dx/da) of the focus cam, becomes smaller than thatin the case where the rotation amount ratio (a_(F) /a_(Z)) is set to be1.0 similarly to the embodiment of Japanese Patent Application Laid-OpenNo. 5-142475, by the influence of the slope (dx/da) of the focus cam.

From Tables 12, 13, and 14, the rate of change, from the infinityin-focus position to the closest in-focus position, of the conversioncoefficient γ_(a) associated with the direction of rotation is ×4.44 atthe wide-angle end (F=28.8), ×5.14 at the middle position (F=70.0), and×6.73 at the telephoto end (F=126.0). When the number N of divisions ofthe focus range upon a change in conversion coefficient γ_(a) in thefirst embodiment is calculated using formula (a), and is compared withthat in the case where the rotation amount ratio (a_(F) /a_(Z)) is setto be 1.0 similarly to the embodiment of Japanese Patent ApplicationLaid-Open No. 5-142475, the numbers N_(W), N_(N), and N_(T) of divisionsat the wide-angle end, middle position, and telephoto end respectivelyhave the following values:

In Case Where Rotation Amount Ratio (a_(F) /a_(Z)) Is Set To Be 1.0

N_(W) >14.6 N_(M) >16.1 N_(T) >16.9

First Embodiment

N_(W) >8.2 N_(M) >9.0 N_(T) >10.5

Therefore, as can be understood from a comparison with the case wherethe ratio of the amounts of rotation (a_(F) /a_(Z)) is set to be 1.0similarly to the embodiment of Japanese Patent Application Laid-Open No.5-142475, the values of the numbers N of divisions become small.

As described above, in the zoom lens of the first embodiment, since therate of change, from the infinity in-focus position to the closestin-focus position, of the conversion coefficient γ_(a) associated withthe direction of rotation becomes much smaller than that in the casewhere the rotation amount ratio (a_(F) /a_(Z)) is set to be 1.0similarly to the embodiment of Japanese Patent Application Laid-Open No.5-142475, the number of data of the conversion coefficient γ_(a) and thecorrection coefficient μ can be reduced, and the storage capacity can besuppressed.

Tables 15, 16, and 17 summarize the calculation results of theconversion coefficient K_(a) and the correction coefficient μ at thewide-angle end (F=28.8), middle position (F=70.0), and telephoto end(F=126.0) according to the first embodiment. In these tables, (R) is theobject distance (m), (ANG) is the amount of rotation for focusing fromthe infinity corresponding position on the focus cam, (r) is theconversion coefficient γ_(a) in the direction of rotation, (rs) is theconversion coefficient K_(a), (bf) is the defocus amount (mm), and (Λ)is the correction coefficient μ. Each table has a matrix structure, andeight rows in the vertical direction indicated by (POS) represent theobject positions (R=10.0, 5.0, 3.0, 2.0, 1.5, 1.0, and 0.8 mm), and fourpairs (R, ANGLE) in the horizontal direction represent the lensarrangements of the focusing lens unit.

More specifically, the position of the focusing lens in the first pairin the upper two tables in each of Tables 15, 16, and 17, i.e., in thethird and fourth columns is (R, ANGLE)=(0.0, 0.0), and it indicates thatthis position corresponds to the infinity corresponding position.Therefore, the third column (r) in the first table represents the valueof the conversion coefficient γ_(a) in the direction of rotation whenthe focusing lens unit is focused on an infinity object, and the fourthcolumn (rs) represents the value of the conversion coefficient K_(a)when the focusing lens unit is moved from an in-focus state on aninfinity object to an in-focus state at the object distance in thesecond column. Furthermore, the third column (bf) in the second tablerepresents the defocus amount ΔBf from a predetermined imaging positionwhen the position of the focusing lens unit corresponds to the infinitycorresponding position, and an object is located at an object distancein the second column, and the fourth column (Λ) represents the value ofthe correction coefficient μ when the focusing lens unit is moved froman in-focus state on an infinity object to an in-focus state at theobject distance in the second column.

Similarly, the position of the focusing lens in the fourth pair in thelower two tables in each of Tables 15, 16, and 17, i.e., in the ninthand tenth columns is (R, ANGLE)=(0.80, 5.5), and it indicates that thisposition corresponds to the closest in-focus (R=0.80 m) correspondingposition. Therefore, the ninth column (r) in the third table representsthe value of the conversion coefficient γ_(a) in the direction ofrotation when the focusing lens unit is focused on a closest distance(R=0.80 m) object, and the tenth column (rs) represents the value of theconversion coefficient K_(a) when the focusing lens unit is moved froman in-focus state on the closest distance (R=0.80 m) object to anin-focus state at the object distance in the second column. Furthermore,the ninth column (bf) in the fourth table represents the defocus amountΔBf from a predetermined imaging position when the position of thefocusing lens unit corresponds to the closest corresponding position,and the object is located at an object distance in the second column,and the tenth column (Λ) represents the value of the correctioncoefficient μ when the focusing lens unit is moved from an in-focusstate on the closest distance (R=0.80 m) object to an in-focus state atthe object distance in the second column.

As described above, since the conversion coefficient in the direction ofrotation is calculated by K_(a) =ΔBf/Δa (where Δa: the amount ofrotation for focusing), and the correction coefficient μ is calculatedby μ=ΔBf/(1-K_(a) /γ_(a)), the value of the conversion coefficient K_(a)(eighth row, fourth column in first table: 0.214) when the focusing lensunit is moved from an in-focus state on the infinity object to anin-focus state at the object distance (R=0.80 m) in Table 15 iscalculated by K_(a) =1.18/5.5=0.214 using ΔBf=1.18 and Δa=5.5. On theother hand, the value of the correction coefficient μ (eighth row,fourth column in second table: -0.95) is calculated as μ=-0.95 usingΔBf=1.18, K_(a) =0.214, and γ_(a) =-0.096.

                                      TABLE 15                                    __________________________________________________________________________    Conversion Coefficients K.sub.a : (rs), γ.sub.a : (r) Associated        with Direction of Rotation and Correction                                     Coefficient μ: (l) at Wide-angle End (28.8 mm) of First Embodiment         f = 28.8 mm                                                                   __________________________________________________________________________    (R,ANGLE) =                                                                            .000                                                                             .000                                                                              10.000                                                                            .840                                                                              5.000                                                                            1.543                                                                             3.000                                                                             2.292                                      POS R    r  rs  r   rs  r  rs  r   rs                                         __________________________________________________________________________    1   .000 .096                                                                             .000    .100   .110    .125                                       2   10.000  .100                                                                              .108                                                                              .000   .122    .139                                       3   5.000   .110    .122                                                                              .138                                                                             .000    .156                                       4   3.000   .125    .139   .156                                                                              .171                                                                              .000                                       5   2.000   .141    .157   .173    .188                                       6   1.500   .158    .175   .192    .210                                       7   1.000   .191    .210   .229    .251                                       8   .800    .214    .235   .256    .279                                       __________________________________________________________________________    POS R    bf l   bf  l   bf l   bf  l                                          __________________________________________________________________________    1   .000 .00                                                                              .00 -.08                                                                              -1.08                                                                             -.17                                                                             -.83                                                                              -.29                                                                              -1.07                                      2   10.000                                                                             .08                                                                              -1.91                                                                             .00 .00 -.09                                                                             -.72                                                                              -.20                                                                              -1.10                                      3   5.000                                                                              .17                                                                              -1.15                                                                             .09 -.69                                                                              .00                                                                              .00 -.12                                                                              -1.34                                      4   3.000                                                                              .29                                                                              -.94                                                                              .20 -.71                                                                              .12                                                                              -.91                                                                              .00 .00                                        5   2.000                                                                              .44                                                                              -.91                                                                              .35 -.79                                                                              .27                                                                              -1.07                                                                             .15 -1.43                                      6   1.500                                                                              .59                                                                              -.91                                                                              .51 -.83                                                                              .42                                                                              -1.09                                                                             .31 -1.32                                      7   1.000                                                                              .92                                                                              -.92                                                                              .84 -.89                                                                              .75                                                                              -1.13                                                                             .63 -1.34                                      8   .800 1.18                                                                             -.95                                                                              1.10                                                                              -.93                                                                              1.01                                                                             -1.19                                                                             .90 -1.41                                      __________________________________________________________________________    (R,ANGLE) =                                                                            2.000                                                                            3.090                                                                             1.500                                                                             3.747                                                                             1.000                                                                            4.813                                                                             .800                                                                              5.500                                      POS R    r  rs  r   rs  r  rs  r   rs                                         __________________________________________________________________________    1   .000    .141    .158   .192    .216                                       2   10.000  .157    .175   .211    .236                                       3   5.000   .173    .192   .230    .257                                       4   3.000   .189    .210   .252    .280                                       5   2.000                                                                              .211                                                                             .000    .237   .281    .310                                       6   1.500   .237                                                                              .264                                                                              .000   .308    .338                                       7   1.000   .281    .308                                                                              .348                                                                             .000    .382                                       8   .800    .309    .337   .382                                                                              .426                                                                              .000                                       __________________________________________________________________________    POS R    bf l   bf  l   bf l   bf  l                                          __________________________________________________________________________    1   .000 -.44                                                                             -1.32                                                                             -.59                                                                              -1.48                                                                             -.92                                                                             -2.05                                                                             -1.19                                                                             -2.40                                      2   10.000                                                                             -.35                                                                             -1.36                                                                             -.51                                                                              -1.51                                                                             -.84                                                                             -2.12                                                                             -1.10                                                                             -2.48                                      3   5.000                                                                              -.27                                                                             -1.46                                                                             -.42                                                                              -1.55                                                                             -.75                                                                             -2.22                                                                             -1.02                                                                             -2.56                                      4   3.000                                                                              -.15                                                                             -1.39                                                                             -.31                                                                              -1.50                                                                             -.64                                                                             -2.30                                                                             -.90                                                                              -2.63                                      5   2.000                                                                              .00                                                                              .00 -.16                                                                              -1.50                                                                             -.48                                                                             -2.51                                                                             -.75                                                                              -2.75                                      6   1.500                                                                              .16                                                                              -1.31                                                                             .00 .00 -.33                                                                             -2.86                                                                             -.59                                                                              -2.85                                      7   1.000                                                                              .48                                                                              -1.48                                                                             .33 -1.98                                                                             .00                                                                              .00 -.26                                                                              -2.56                                      8   .800 .75                                                                              -1.61                                                                             .59 -2.15                                                                             .26                                                                              -2.74                                                                             .00 .00                                        __________________________________________________________________________     Condition Corresponding Values: K.sub.aO /γ.sub.aO = 2.23, K.sub.aR     /γ.sub.aR = 0.51                                                   

                                      TABLE 16                                    __________________________________________________________________________    Conversion Coefficients K.sub.a : (rs), γ.sub.a : (r) Associated        with Direction of Rotation and Correction                                     Coefficient μ: (l) at Middle Position (70.0 mm) of First Embodiment        f = 70.0 mm                                                                   __________________________________________________________________________    (R,ANGLE) =                                                                            .000                                                                             .000                                                                              10.000                                                                            .840                                                                              5.000                                                                            1.512                                                                             3.000                                                                             2.255                                      POS R    r  rs  r   rs  r  rs  r   rs                                         __________________________________________________________________________    1   .000 .508                                                                             .000    .590   .664    .754                                       2   10.000  .589                                                                              .677                                                                              .000   .755    .850                                       3   5.000   .662    .754                                                                              .835                                                                             .000    .935                                       4   3.000   .750    .847   .933                                                                              1.037                                                                             .000                                       5   2.000   .851    .954   1.044   1.153                                      6   1.500   .947    1.054  1.148   1.262                                      7   1.000   1.129   1.245  1.347   1.471                                      8   .800    1.271   1.397  1.508   1.643                                      __________________________________________________________________________    POS R    bf l   bf  l   bf l   bf  l                                          __________________________________________________________________________    1   .000 .00                                                                              .00 -.50                                                                              -3.87                                                                             -1.00                                                                            -4.90                                                                             -1.70                                                                             -6.22                                      2   10.000                                                                             .50                                                                              -3.08                                                                             .00 .00 -.51                                                                             -5.29                                                                             -1.20                                                                             -6.66                                      3   5.000                                                                              1.00                                                                             -3.30                                                                             .51 -4.45                                                                             .00                                                                              .00 -.69                                                                              -7.01                                      4   3.000                                                                              1.69                                                                             -3.54                                                                             1.20                                                                              -4.77                                                                             .69                                                                              -5.92                                                                             .00 .00                                        5   2.000                                                                              2.58                                                                             -3.81                                                                             2.09                                                                              -5.11                                                                             1.59                                                                             -6.34                                                                             .90 -8.05                                      6   1.500                                                                              3.51                                                                             -4.05                                                                             3.02                                                                              -5.41                                                                             2.52                                                                             -6.71                                                                             1.83                                                                              -8.45                                      7   1.000                                                                              5.46                                                                             -4.46                                                                             4.97                                                                              -5.92                                                                             4.48                                                                             -7.30                                                                             3.80                                                                              -9.09                                      8   .800 7.02                                                                             -4.67                                                                             6.54                                                                              -6.15                                                                             6.05                                                                             -7.51                                                                             5.37                                                                              -9.21                                      __________________________________________________________________________    (R,ANGLE)                                                                              2.000                                                                            3.033                                                                             1.500                                                                             3.703                                                                             1.000                                                                            4.836                                                                             .800                                                                              5.526                                      POS R    r  rs  r   rs  r  rs  r   rs                                         __________________________________________________________________________    1   .000    .858    .956   1.142   1.287                                      2   10.000  .959    1.062  1.258   1.412                                      3   5.000   1.049   1.155  1.359   1.522                                      4   3.000   1.156   1.267  1.481   1.655                                      5   2.000                                                                              1.278                                                                            .000    1.394  1.620   1.811                                      6   1.500   1.391                                                                             1.510                                                                             .000   1.752   1.964                                      7   1.000   1.613   1.748                                                                             2.048                                                                            .000    2.314                                      8   .800    1.802   1.958  2.312                                                                             2.612                                                                             .000                                       __________________________________________________________________________    POS R    bf l   bf  l   bf l   bf  l                                          __________________________________________________________________________    1   .000 -2.60                                                                            -7.91                                                                             -3.54                                                                             -9.64                                                                             -5.52                                                                            -12.49                                                                            -7.11                                                                             -14.02                                     2   10.000                                                                             -2.10                                                                            -8.44                                                                             -3.04                                                                             -10.24                                                                            -5.03                                                                            -13.03                                                                            -6.62                                                                             -14.40                                     3   5.000                                                                              -1.59                                                                            -8.88                                                                             -2.53                                                                             -10.76                                                                            -4.52                                                                            -13.43                                                                            -6.11                                                                             -14.63                                     4   3.000                                                                              -.90                                                                             -9.38                                                                             -1.83                                                                             -11.37                                                                            -3.82                                                                            -13.79                                                                            -5.41                                                                             -14.78                                     5   2.000                                                                              .00                                                                              .00 -.93                                                                              -12.11                                                                            -2.92                                                                            -13.96                                                                            -4.51                                                                             -14.72                                     6   1.500                                                                              .93                                                                              -10.52                                                                            .00 .00 -1.98                                                                            -13.75                                                                            -3.58                                                                             -14.44                                     7   1.000                                                                              2.91                                                                             -11.10                                                                            1.98                                                                              -12.59                                                                            .00                                                                              .00 -1.60                                                                             -13.98                                     8   .800 4.49                                                                             -10.96                                                                            3.57                                                                              -12.04                                                                            1.60                                                                             -12.37                                                                            .00 .00                                        __________________________________________________________________________     Condition Corresponding Values: K.sub.aO /γ.sub.aO = 2.50, K.sub.aR     /γ.sub.aR = 0.49                                                   

                                      TABLE 17                                    __________________________________________________________________________    Conversion Coefficients K.sub.a : (rs), γ.sub.a : (r) Associated        with Direction of Rotation and Correction                                     Coefficient μ: (l) at Telephoto End (126.0 mm) of First Embodiment         f = 126.0 mm                                                                  __________________________________________________________________________    (R, ANGLE) =                                                                         .000                                                                              .000                                                                              10.000                                                                            .855                                                                              5.000                                                                             1.543                                                                             3.000                                                                             2.292                                      POS                                                                              R   r   rs  r   rs  r   rs  r   rs                                         __________________________________________________________________________    1  .000                                                                              1.675                                                                             .000    1.8976  2.147   2.471                                      2  10.000  1.889                                                                             2.163                                                                             .000    2.454   2.813                                      3  5.000   2.132   2.447                                                                             2.777                                                                             .000    3.143                                      4  3.000   2.450   2.801   3.138                                                                             3.486                                                                             .000                                       5  2.000   2.812   3.188   3.545   3.922                                      6  1.500   3.192   3.607   3.993   4.456                                      7  1.000   3.988   4.488   4.959   5.548                                      8  .800    4.602   5.165   5.698   6.367                                      __________________________________________________________________________    POS                                                                              R   bf  l   bf  l   bf  l   bf  l                                          __________________________________________________________________________    1  .000                                                                              .00 .00 -1.62                                                                             -13.154                                                                           -3.31                                                                             -14.59                                                                            -5.66                                                                             -19.44                                     2  10.000                                                                            1.62                                                                              -12.66                                                                            .00 .00 -1.69                                                                             -14.50                                                                            -4.04                                                                             -20.91                                     3  5.000                                                                             3.29                                                                              -12.06                                                                            1.68                                                                              -12.85                                                                            .00 .00 -2.35                                                                             -23.90                                     4  3.000                                                                             5.62                                                                              -12.13                                                                            4.02                                                                              -13.66                                                                            2.35                                                                              -18.05                                                                            .00 .00                                        5  2.000                                                                             8.69                                                                              -12.80                                                                            7.12                                                                              -15.04                                                                            5.47                                                                              -20.02                                                                            3.13                                                                              -25.02                                     6  1.500                                                                             11.96                                                                             -13.021                                                                           10.54                                                                             -15.64                                                                            8.80                                                                              -20.10                                                                            6.48                                                                              -23.31                                     7  1.000                                                                             19.19                                                                             -13.90                                                                            17.76                                                                             -16.53                                                                            16.232                                                                            -20.63                                                                            13.98                                                                             -23.65                                     8  .800                                                                              25.31                                                                             -14.48                                                                            23.99                                                                             -17.29                                                                            22.55                                                                             -21.43                                                                            20.43                                                                             -24.72                                     __________________________________________________________________________    (R, ANGLE) =                                                                         2.000                                                                             3.090                                                                             1.500                                                                             3.747                                                                             1.000                                                                             4.813                                                                             .800                                                                              5.500                                      POS                                                                              R   r   rs  r   rs  r   rs  r   rs                                         __________________________________________________________________________    1  .000    2.831   3.193   3.881   4.326                                      2  10.000  3.195   3.591   4.345   4.825                                      3  5.000   3.533   3.964   4.783   5.298                                      4  3.000   3.914   4.416   5.337   5.898                                      5  2.000                                                                             4.468                                                                             .000    5.075   6.100   6.705                                      6  1.500   5.111                                                                             5.827                                                                             .000    6.863   7.502                                      7  1.000   6.335   7.082                                                                             7.993                                                                             .000    9.032                                      8  .800    7.242   8.061   9.421                                                                             11.264                                                                            .000                                       __________________________________________________________________________    POS                                                                              R   bf  l   bf  l   bf  l   bf  l                                          __________________________________________________________________________    1  .000                                                                              -8.75                                                                             -23.87                                                                            -11.97                                                                            -26.47                                                                            -18.68                                                                            -36.31                                                                            -23.79                                                                            -38.63                                     2  10.000                                                                            -7.14                                                                             -25.06                                                                            -10.37                                                                            -27.07                                                                            -17.19                                                                            -37.67                                                                            -22.41                                                                            -39.21                                     3  5.000                                                                             -5.46                                                                             -26.11                                                                            -8.74                                                                             -27.33                                                                            -15.64                                                                            -38.95                                                                            -20.96                                                                            -39.58                                     4  3.000                                                                             -3.12                                                                             -25.19                                                                            "6.43                                                                             -26.55                                                                            -13.45                                                                            -40.48                                                                            -18.92                                                                            -39.71                                     5  2.000                                                                             .00 .00 -3.34                                                                             -25.88                                                                            -10.51                                                                            -44.39                                                                            -16.16                                                                            -39.93                                     6  1.500                                                                             3.36                                                                              -23.34                                                                            .00 .00 -7.31                                                                             -51.75                                                                            -13.15                                                                            -39.37                                     7  1.000                                                                             10.92                                                                             -26.12                                                                            7.55                                                                              -35.03                                                                            .00 .00 -6.21                                                                             -31.33                                     8  .800                                                                              17.46                                                                             -28.12                                                                            14.13                                                                             -36.85                                                                            6.48                                                                              -36.26                                                                            .00 .00                                        __________________________________________________________________________     Condition Corresponding Values; K.sub.a0 /γ.sub.a0 = 2.75, K.sub.aR     /γ.sub.aR = 0.38                                                   

As can be seen from Tables 15, 16, and 17 above, when a change inconversion coefficient K_(a) : (rs) (e.g., the fourth column in thefirst table) at a given lens arrangement (e.g., at the infinity in-focusarrangement) is considered, the rate of change becomes small as comparedto the change in K_(a) (Tables 6, 7, and 8) in the case where therotation amount ratio (a_(F) /a_(Z)) is set to be 1.0 similarly to theembodiment of Japanese Patent Application Laid-Open No. 5-142475examined previously.

More specifically, the amount Δa of rotation for focusing in the firstembodiment at the infinity object side becomes relatively smaller thanthat at the closest object side, as compared to the case where therotation amount ratio (a_(F) /a_(Z)) is set to be 1.0 similarly to theembodiment of Japanese Patent Application Laid-Open No. 5-142475. Infact, when the ratio between the amount of rotation for focusing uponfocusing to the closest distance and the amount of rotation for focusingupon focusing to the object distance (R=5.0 m) is calculated in Tables 1and 10, 4.296/10.0=0.430 in the case where the rotation amount ratio(a_(F) /a_(Z)) is set to be 1.0 similarly to the embodiment of JapanesePatent Application Laid-Open No. 5-142475, while 1.543/5.5=0.281 in thefirst embodiment. As described above, when the focus cam with thearrangement of the present invention is used, since the amount Δa ofrotation for focusing becomes relatively smaller at the infinity objectside, the conversion coefficient K_(a) becomes relatively large at theinfinity object side, and consequently, the change in conversioncoefficient K_(a) in the direction of rotation can be reduced ascompared to the conventional system.

The calculation results of the rate of change of K_(a) with respect toγ_(a) at the infinity in-focus arrangement and the closest in-focusarrangement at the wide-angle end (F=28.8), middle position (F=70.0),and telephoto end (F=126.0) in the case where the rotation amount ratio(a_(F) /a_(Z)) is set to be 1.0 similarly to the embodiment of JapanesePatent Application Laid-Open No. 5-142475 and in the first embodiment ofthe present invention where the rotation amount ratio (a_(F) /a_(Z)) isset to be 0.55 are as follows.

    ______________________________________                                        In Case Where Rotation Amount Ratio (a.sub.F /a.sub.Z) Is Set To Be 1.0                Infinity Arrangement                                                                       Closest Arrangement                                              K.sub.aO /γ.sub.aO                                                                   K.sub.aR /γ.sub.aR                                ______________________________________                                        Wide-angle End                                                                           4.76           0.34                                                (F = 28.8)                                                                    Middle Position                                                                          5.78           0.31                                                (F = 70.0)                                                                    Telephoto End                                                                            6.58           0.28                                                (F = 126.0)                                                                   First Embodiment                                                              Wide-angle End                                                                           2.23           0.51                                                (F = 28.8)                                                                    Middle Position                                                                          2.50           0.49                                                (F = 70.0)                                                                    Telephoto End                                                                            2.75           0.38                                                (F = 126.0)                                                                   ______________________________________                                    

As described above, according to the present invention, since the rateof change of K_(a) with respect to γ_(a) is small as compared to theconventional system, and the contribution of the correction term (ΔBf/μ)in K_(a) =γ_(a) (1-ΔBf/μ) can be reduced, the value of the correctioncoefficient μ can be set to be large as compared to the defocus amountΔBf, and at the same time, the change in correction coefficient μ can bedecreased.

Therefore, even when only a pair of a conversion coefficient γ_(a) valueand a correction coefficient μ value are set for a given lensarrangement range, an error in the conversion coefficient K_(a)calculated using γ_(a) and μ or in the actual lens driving amount Δa forfocusing can be eliminated.

Next, in the case where the rotation amount ratio (a_(F) /a_(Z)) is setto be 1.0 similarly to the embodiment of Japanese Patent ApplicationLaid-Open No. 5-142475 and the first embodiment of the present inventionwhere the rotation amount ratio (a_(F) /a_(Z)) is set to be 0.55, whenthe lens driving amounts upon focusing from the infinity in-focus lensarrangement to the closest distance object and upon focusing from theclosest in-focus lens arrangement to the infinity object at thewide-angle end (F=28.8), middle position (F=70.0), and telephoto end(F=126.0) are calculated from Δa=ΔBf/ γ_(a) (1-ΔBf/μ)!, and errors fromthe actual lens driving amounts are then calculated, the followingvalues are obtained. Note that the value of the correction coefficient μupon focusing from the infinity in-focus lens arrangement to the closestdistance object adopts a value at the object distance (POS-5), and thevalue of the correction coefficient μ upon focusing from the closestin-focus lens arrangement to the infinity object adopts a value at theobject distance (POS-4).

    ______________________________________                                        In Case Where Rotation Amount Ratio (a.sub.F /a.sub.Z) Is Set To Be 1.0                Infinity Arrangement →                                                              Closest Arrangement →                                     Closest In-focus State                                                                     Infinity In-focus State                                 ______________________________________                                        Wide-angle End                                                                           -8.7%          -26.3%                                              (F = 28.8)                                                                    Middle Position                                                                          -13.2%         -23.4%                                              (F = 70.0)                                                                    Telephoto End                                                                            -14.1%         -28.7%                                              (F = 126.0)                                                                   First Embodiment                                                              Wide-angle End                                                                           -2.7%          -7.2%                                               (F = 28.8)                                                                    Middle Position                                                                          -12.0%         -5.1%                                               (F = 70.0)                                                                    Telephoto End                                                                            -7.7%          -4.2%                                               (F = 126.0)                                                                   ______________________________________                                    

As described above, even when only a pair of a conversion coefficientγ_(a) value and a correction coefficient μ value are set for a givenlens arrangement range, an error between the conversion coefficientK_(a) calculated from γ_(a) and μ and the lens driving amount Δa forfocusing becomes small as compared to the conventional system, andfocusing can be realized with higher accuracy.

Next, an examination will be made as to whether not only accurateauto-focusing but also so-called manual focusing can be attained in thezoom lens of the first embodiment.

Table 18 summarizes the amount (ANGLE DA) of rotation for focusing uponmanual focusing using the focus cam (the middle table in Table 10) ofthe first embodiment, the amount DX (mm) of movement, in the directionof the optical axis, of the focusing lens unit corresponding to theamount of rotation for focusing, and the displacement amount Bf (mm) ofthe imaging point when the amount (DX) of movement in the direction ofthe optical axis is given.

The upper table in Table 18 summarizes the displacement amount (Bf) ofthe imaging point corresponding to the photographing distances (R=5.0,3.0, 2.0, 1.5, 1.0, and 0.8 m) in the respective zooming states of thefocal lengths (F=28.8, 35.0, 50.0, 70.0, 95.0, and 126.0 mm), and themiddle table summarizes the values of the amount (ANGLE DA) of rotationfor focusing required for attaining an optimal in-focus state withrespect to the respective photographing distances (R=5.0, 3.0, 2.0, 1.5,1.0, and 0.8 m). Note that the amounts of rotation for focusing, whichhave values for eliminating any displacement of the imaging point at thewide-angle end and the telephoto end, are selected. The lower tablesummarizes the amounts (DX) of movement, in the direction of the opticalaxis, of the respective lens units corresponding to the amount (ANGLEDA) of rotation for focusing in association with the photographingdistances (R=5.0, 3.0, 2.0, 1.5, 1.0, and 0.8 m) in the respectivezooming states with the focal lengths (F=28.8, 35.0, 50.0, 70.0, 95.0,and 126.0 mm). In the lower table, (F) is the focal length (mm) of theentire system, (R) is the photographing distance (m), and (DX) is theamount (mm) of movement, in the direction of the optical axis, of eachof the first, second, third, fourth, and fifth lens units in turn fromthe right side. Note that the amount of movement in the direction of theoptical axis toward the object side is represented by a positive value.

                                      TABLE 18                                    __________________________________________________________________________    Displacement Amount Bf (mm) of Imaging Point and Amount DX                    (mm) of movement for focusing in First Embodiment                                         0.80 m                                                                            1.00 m                                                                             1.50 m                                                                            2.00 m                                                                             3.00 m                                                                            5.00 m                                      __________________________________________________________________________    F  28.800                                                                             Bf  .000                                                                              .000 .000                                                                              .000 .000                                                                              .000                                        F  35.000                                                                             Bf  -.011                                                                             .015 .004                                                                              .000 .006                                                                              .000                                        F  50.000                                                                             Bf  -.035                                                                             -.001                                                                              .019                                                                              .030 .038                                                                              .015                                        F  70.000                                                                             Bf  .068                                                                              .047 -.067                                                                             -.073                                                                              -.038                                                                             .026                                        F  95.000                                                                             Bf  -.007                                                                             .052 -.020                                                                             -.019                                                                              -.041                                                                             -.085                                       F  126.000                                                                            Bf  .000                                                                              .000 .000                                                                              .000 .000                                                                              .000                                           ANGLE                                                                              DA  5.500                                                                             4.813                                                                              3.747                                                                             3.090                                                                              2.292                                                                             1.543                                       F 28.800                                                                             DX  000 .000                                                                              .000                                                                              -.365                                                                              .000                                                                              R  0.80 m                                     F 35.000                                                                             DX  .000                                                                              .000                                                                              .000                                                                              -.537                                                                              .000                                                                              R  0.80 m                                     F 50.000                                                                             DX  .000                                                                              .000                                                                              .000                                                                              -1.071                                                                             .000                                                                              R  0.80 m                                     F 70.000                                                                             DX  .000                                                                              .000                                                                              .000                                                                              -2.001                                                                             .000                                                                              R  0.80 m                                     F 95.000                                                                             DX  .000                                                                              .000                                                                              .000                                                                              -3.658                                                                             .000                                                                              R  0.80 m                                     F 126.000                                                                            DX  .000                                                                              .000                                                                              .000                                                                              -6.367                                                                             .000                                                                              R  0.80 m                                     F 28.800                                                                             DX  .000                                                                              .000                                                                              .000                                                                              -.284                                                                              .000                                                                              R  1.00 m                                     F 35.000                                                                             DX  .000                                                                              .000                                                                              .000                                                                              -.411                                                                              .000                                                                              R  1.00 m                                     F 50.000                                                                             DX  .000                                                                              .000                                                                              .000                                                                              -.829                                                                              .000                                                                              R  1.00 m                                     F 70.000                                                                             DX  .000                                                                              .000                                                                              .000                                                                              -1.565                                                                             .000                                                                              R  1.00 m                                     F 95.000                                                                             DX  .000                                                                              .000                                                                              .000                                                                              -2.843                                                                             .000                                                                              R  1.00 m                                     F 126.000                                                                            DX  .000                                                                              .000                                                                              .000                                                                              -4.956                                                                             .000                                                                              R  1.00 m                                     F 28.800                                                                             DX  .000                                                                              .000                                                                              .000                                                                              -.183                                                                              .000                                                                              R  1.50 m                                     F 35.000                                                                             DX  .000                                                                              .000                                                                              .000                                                                              -.267                                                                              .000                                                                              R  1.50 m                                     F 50.000                                                                             DX  .000                                                                              .000                                                                              .000                                                                              -.530                                                                              .000                                                                              R  1.50 m                                     F 70.000                                                                             DX  .000                                                                              .000                                                                              .000                                                                              -1.040                                                                             .000                                                                              R  1.50 m                                     F 95.000                                                                             DX  .000                                                                              .000                                                                              .000                                                                              -1.853                                                                             .000                                                                              R  1.50 m                                     F 126.000                                                                            DX  .000                                                                              .000                                                                              .000                                                                              -3.190                                                                             .000                                                                              R  1.50 m                                     F 28.800                                                                             DX  .000                                                                              .000                                                                              .000                                                                              -.135                                                                              .000                                                                              R  2.00 m                                     F 35.000                                                                             DX  .000                                                                              .000                                                                              .000                                                                              -.198                                                                              .000                                                                              R  2.00 m                                     F 50.000                                                                             DX  .000                                                                              .000                                                                              .000                                                                              -.386                                                                              .000                                                                              R  2.00 m                                     F 70.000                                                                             DX  .000                                                                              .000                                                                              .000                                                                              -.775                                                                              .000                                                                              R  2.00 m                                     F 95.000                                                                             DX  .000                                                                              .000                                                                              .000                                                                              -1.370                                                                             .000                                                                              R  2.00 m                                     F 126.000                                                                            DX  .000                                                                              .000                                                                              .000                                                                              -2.352                                                                             .000                                                                              R  2.00 m                                     F 28.800                                                                             DX  .000                                                                              .000                                                                              .000                                                                              -.089                                                                              .000                                                                              R  3.00 m                                     F 35.000                                                                             DX  .000                                                                              .000                                                                              .000                                                                              -.128                                                                              .000                                                                              R  3.00 m                                     F 50.000                                                                             DX  .000                                                                              .000                                                                              .000                                                                              -.248                                                                              .000                                                                              R  3.00 m                                     F 70.000                                                                             DX  .000                                                                              .000                                                                              .000                                                                              -.507                                                                              .000                                                                              R  3.00 m                                     F 95.000                                                                             DX  .000                                                                              .000                                                                              .000                                                                              -.908                                                                              .000                                                                              R  3.00 m                                     F 126.000                                                                            DX  .000                                                                              .000                                                                              .000                                                                              -1.542                                                                             .000                                                                              R  3.00 m                                     F 28.000                                                                             DX  .000                                                                              .000                                                                              .000                                                                              -.052                                                                              .000                                                                              R  5.00 m                                     F 35.000                                                                             DX  .000                                                                              .000                                                                              .000                                                                              -.077                                                                              .000                                                                              R  5.00 m                                     F 50.000                                                                             DX  .000                                                                              .000                                                                              .000                                                                              -.149                                                                              .000                                                                              R  5.00 m                                     F 70.000                                                                             DX  .000                                                                              .000                                                                              .000                                                                              -.301                                                                              .000                                                                              R  5.00 m                                     F 95.000                                                                             DX  .000                                                                              .000                                                                              .000                                                                              -.556                                                                              .000                                                                              R  5.00 m                                     F 126.000                                                                            DX  .000                                                                              .000                                                                              .000                                                                              -.913                                                                              .000                                                                              R  5.00 m                                     __________________________________________________________________________

As can be seen from Table 18, so-called manual focusing can be attainedsince the displacement amounts of the imaging point at the respectivefocal lengths and photographing distances are very small, and fallwithin the depth of focus independently of the zooming state andphotographing distance.

Second Embodiment!

The second embodiment is directed to a zoom lens which has a five-unitarrangement, i.e., positive, negative, positive, negative and positivelens units, and attains focusing by a negative second lens unit. In thiszoom lens, the rotation amount ratio (a_(F) /a_(Z)) of the rotationamount for focusing from the infinity in-focus position to the closestin-focus position (R=0.80 m) to the amount of rotation for zooming fromthe wide-angle end (F=28.8) to the telephoto end (F=131.0) is set to be0.75.

Table 19 below summarizes various paraxial data of an optical system anddata for defining the shape of a focus cam according to the secondembodiment.

The upper table in Table 19 summarizes the focal lengths and principalpoint interval data of the respective lens units of the optical systemcorresponding to the second embodiment in association with six zoomingstates (focal length F=28.8 (1-POS), 35.0 (2-POS), 50.0 (3-POS), 70.0(4-POS), 105.0 (5-POS), and 131.0 mm (6-POS)).

The middle table in Table 19 summarizes spline sample data when theshape of the focus cam in the second lens unit of the second embodiment,which is used for focusing, is expressed by the above-mentioned splinefunction associated with the angle a of rotation of a rotatable lensbarrel and the amount x of movement in the direction of the opticalaxis. In this middle table, (1), (2), (3), (4), and (5) correspond tothe first, second, third, fourth, and fifth lens units, respectively.

Furthermore, the lower table in Table 19 summarizes the infinityfocusing positions (infinity corresponding positions) at the respectivefocal lengths (focal length F=28.8, 35.0, 50.0, 70.0, 105.0, and 131.0mm), and the amounts of rotation (amounts of rotation for focusing) uponfocusing to respective photographing distances (R=5.0, 3.0, 2.0, 1.5,1.0, and 0.8 m) using the focus cam of the second embodiment. In thistable, since the amount of rotation for zooming from the wide-angle end(F=28.8) to the telephoto end (F=131.0) is set to be 10.0, and theamount of rotation for focusing from the infinity in-focus position tothe closest in-focus position (R=0.80 m) is set to be 7.5, the rotationamount ratio (a_(F) /a_(Z)) of the amount of rotation for focusing tothe amount of rotation for zooming in the second embodiment is 0.75.

                                      TABLE 19                                    __________________________________________________________________________    Second Embodiment f = 28.8 to 131.0 (Rotation Amount Ratio: a.sub.p           /a.sub.z = 0.75)                                                              __________________________________________________________________________    Focal lengths and Principal Point Intervals of Lens Units of Second           Embodiment                                                                              1-POS                                                                              2-POS                                                                             3-POS                                                                              4-POS                                                                             5-POS                                                                              6-POS                                        __________________________________________________________________________            F 28.8000                                                                            35.0000                                                                           50.0000                                                                            70.0000                                                                           105.0000                                                                           131.0000                                     F1 77.2000                                                                            D1                                                                              10.3313                                                                            15.1893                                                                           23.5104                                                                            30.7072                                                                           38.5116                                                                            42.3545                                      F2 -14.7000                                                                           D2                                                                              27.6049                                                                            24.9667                                                                           20.7775                                                                            17.3207                                                                           13.3359                                                                            11.0136                                      F3 21.3000                                                                            D3                                                                              6.0146                                                                             7.0237                                                                            8.9018                                                                             10.6018                                                                           12.3379                                                                            13.0291                                      F4 -37.0000                                                                           D4                                                                              9.0353                                                                             8.0262                                                                            6.1481                                                                             4.4481                                                                            2.7120                                                                             2.0208                                       F5 60.0000                                                                            D5                                                                              50.6898                                                                            52.5061                                                                           55.8867                                                                            58.9468                                                                           62.0719                                                                            63.3160                                      __________________________________________________________________________    Focus Cam Shape (Spline Interpolation Sample Point)                           Corresponding to Second Embodiment                                                 ANGLE (1)  (2)    (3)  (4)  (5)                                          __________________________________________________________________________    1    .0000 .0000                                                                              .0000  .0000                                                                              .0000                                                                              .0000                                        2    2.5416                                                                              .0000                                                                              .1038  .0000                                                                              .0000                                                                              .0000                                        3    3.5918                                                                              .0000                                                                              .1740  .0000                                                                              .0000                                                                              .0000                                        4    4.6092                                                                              .0000                                                                              .2632  .0000                                                                              .0000                                                                              .0000                                        5    5.4239                                                                              .0000                                                                              .3538  .0000                                                                              .0000                                                                              .0000                                        6    6.7186                                                                              .0000                                                                              .5397  .0000                                                                              .0000                                                                              .0000                                        7    7.5000                                                                              .0000                                                                              .6835  .0000                                                                              .0000                                                                              .0000                                        8    10.0000                                                                             .0000                                                                              1.3493 .0000                                                                              .0000                                                                              .0000                                        9    12.5416                                                                             .0000                                                                              2.4807 .0000                                                                              .0000                                                                              .0000                                        10   13.5918                                                                             .0000                                                                              3.0742 .0000                                                                              .0000                                                                              .0000                                        11   14.6092                                                                             .0000                                                                              3.7117 .0000                                                                              .0000                                                                              .0000                                        12   15.4239                                                                             .0000                                                                              4.2697 .0000                                                                              .0000                                                                              .0000                                        13   16.7186                                                                             .0000                                                                              5.2286 .0000                                                                              .0000                                                                              .0000                                        14   17.5000                                                                             .0000                                                                              5.8545 .0000                                                                              .0000                                                                              .0000                                        15   20.0000                                                                             0000 8.2500 .0000                                                                              .0000                                                                              .0000                                        __________________________________________________________________________    Amount of Rotation for Zooming and Amount of Rotation for Focusing of         Second Embodiment                                                             (Rotation Amount Ratio: a.sub.p /a.sub.z = 0.75)                                       Infinity            Amount of                                                 Corresponding                                                                          Photographing                                                                            Rotation for                                     Focal Length                                                                           Position Distance   Focusing                                         __________________________________________________________________________    28.8                                                                              mm   .0000    5.00 m     2.542                                            35.0                                                                              mm   0.8015   3.00 m     3.592                                            50.0                                                                              mm   2.4118   2.00 m     4.609                                            70.0                                                                              mm   4.2101   1.50 m     5.424                                            105.0                                                                             mm   7.3192   1.00 m     6.719                                            131.0                                                                             mm   10.0000  0.80 m     7.500                                            Condition Corresponding Value (1)                                                               1.76                                                        Condition Corresponding Value (2)                                                               6.59                                                        Condition Corresponding Value (3)                                                               0.75                                                        Condition Corresponding Value (4)                                                               6.25 (wide-angle end)                                                                    4.23 (telephoto end)                             Condition Corresponding Value (5)                                                               2.92 (wide-angle end)                                                                    4.47 (telephoto end)                             Condition Corresponding Value (6)                                                               0.43 (wide-angle end)                                                                    0.39 (telephoto end)                             __________________________________________________________________________

Table 20 below summarizes the numerical value data of the cams of thefocusing lens unit in the second embodiment, which data are calculatedby interpolation based on a spline function on the basis of the sampledata of the focus cam summarized in the middle table in Table 19. Notethat the meanings of the reference symbols in Table 20 are the same asthose in the first embodiment.

                  TABLE 20                                                        ______________________________________                                        Cam Numerical Value Data of Focusing Lens Unit in Third Embodiment                             Zoom Compensation Cam                                        Focus Cam Numerical Value Data                                                                 Numerical Value Data                                         ANGLE (2)      F         ANGLE  (2)    F                                      ______________________________________                                        .0000 .0000    28.8000   .0000  .0000  28.8000                                .5000 .0165    32.5682   .5000  -.5738 32.5682                                1.0000                                                                              .0340    36.6673   1.0000 -1.0051                                                                              36.6673                                1.5000                                                                              .0533    41.0965   1.5000 -1.3271                                                                              41.0965                                2.0000                                                                              .0755    45.8495   2.0000 -1.5692                                                                              45.8495                                2.5000                                                                              .1014    50.9157   2.5000 -1.7573                                                                              50.9157                                3.0000                                                                              .1319    56.2691   3.0000 -1.9131                                                                              56.2691                                3.5000                                                                              .1671    61.8430   3.5000 -2.0535                                                                              61.8430                                4.0000                                                                              .2070    67.5683   4.0000 -2.1922                                                                              67.5683                                4.5000                                                                              .2524    73.3649   4.5000 -2.3393                                                                              73.3649                                5.0000                                                                              .3044    79.1609   5.0000 -2.5020                                                                              79.1609                                5.5000                                                                              .3632    84.9148   5.5000 -2.6842                                                                              84.9148                                6.0000                                                                              .4293    90.5921   6.0000 -2.8878                                                                              90.5921                                6.5000                                                                              .5040    96.1493   6.5000 -3.1138                                                                              96.1493                                7.0000                                                                              .5886    101.5829  7.0000 -3.3632                                                                              101.5829                               7.5000                                                                              .6835    106.9179  7.5000 -3.6365                                                                              106.9179                               8.0000                                                                              .7887    112.1347  8.0000 -3.9323                                                                              112.1347                               8.5000                                                                              .9058    117.1701  8.5000 -4.2485                                                                              117.1701                               9.0000                                                                              1.0370   121.9832  9.0000 -4.5837                                                                              121.9832                               9.5000                                                                              1.1841   126.5510  9.5000 -4.9369                                                                              126.5510                               10.0000                                                                             1.3493   131.0000  10.0000                                                                              -5.3145                                                                              131.0000                               10.5000                                                                             1.5343   .0000                                                          11.0000                                                                             1.7385   .0000                                                          11.5000                                                                             1.9611   .0000                                                          12.0000                                                                             2.2015   .0000                                                          12.5000                                                                             2.4585   .0000                                                          13.0000                                                                             2.7316   .0000                                                          13.5000                                                                             3.0197   .0000                                                          14.0000                                                                             3.3223   .0000                                                          14.5000                                                                             3.6401   .0000                                                          15.0000                                                                             3.9744   .0000                                                          15.5000                                                                             4.3237   .0000                                                          16.0000                                                                             4.6862   .0000                                                          16.5000                                                                             5.0610   .0000                                                          17.0000                                                                             5.4478   .0000                                                          17.5000                                                                             5.8545   .0000                                                          ______________________________________                                    

The left table in Table 20 summarizes the numerical value data of thefocus cam of the second embodiment, and the right table in Table 20summarizes the numerical value data of the zoom compensation cam of thisembodiment. A value obtained by synthesizing the amounts (2) of movementin the direction of the optical axis in the numerical value data of thefocus cam and the zoom compensation cam in the range from the amount ofrotation (ANGLE=0.0) to the amount of rotation (ANGLE=10.0) coincideswith the movement locus of the second lens unit calculated using theparaxial data in the upper table in Table 19.

Tables 21, 22, and 23 below summarize the amount DX (mm) of movement forfocusing, in the direction of the optical axis, of the focusing lensunit, the imaging magnifications β_(K) of the respective lens units, theconversion coefficient γ_(x) associated with the direction of theoptical axis, the slope (dx/da) of the focus cam, and the conversioncoefficient γ_(a) associated with the direction of rotation at thewide-angle end (F=28.8), the middle position (F=70.0), and the telephotoend (F=131.0) according to the second embodiment, respectively. Thearrangements of the respective tables and the meanings of the referencesymbols are the same as those in the first embodiment.

                                      TABLE 21                                    __________________________________________________________________________    Amount (DX) (mm) of Movement for Focusing in Direction of Optical Axis        at                                                                            Wide-angle End (28.8 mm) in Second Embodiment                                 R  .000                                                                              ANG                                                                              .000                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                             4)                                                                              .000                                                                              5)                                                                              .000                                      R  10.000                                                                            ANG                                                                              1.459                                                                            1)                                                                              .000                                                                             2)                                                                              .052                                                                             3)                                                                              .000                                                                             4)                                                                              .000                                                                              5)                                                                              .000                                      R  5.000                                                                             ANG                                                                              2.542                                                                            1)                                                                              .000                                                                             2)                                                                              .104                                                                             3)                                                                              .000                                                                             4)                                                                              .000                                                                              5)                                                                              .000                                      R  3.000                                                                             ANG                                                                              3.592                                                                            1)                                                                              .000                                                                             2)                                                                              .174                                                                             3)                                                                              .000                                                                             4)                                                                              .000                                                                              5)                                                                              .000                                      R  2.000                                                                             ANG                                                                              4.609                                                                            1)                                                                              .000                                                                             2)                                                                              .263                                                                             3)                                                                              .000                                                                             4)                                                                              .000                                                                              5)                                                                              .000                                      R  1.500                                                                             ANG                                                                              5.424                                                                            1)                                                                              .000                                                                             2)                                                                              .354                                                                             3)                                                                              .000                                                                             4)                                                                              .000                                                                              5)                                                                              .000                                      R  1.000                                                                             ANG                                                                              6.719                                                                            1)                                                                              .000                                                                             2)                                                                              .540                                                                             3)                                                                              .000                                                                             4)                                                                              .000                                                                              5)                                                                              .000                                      R  .800                                                                              ANG                                                                              7.500                                                                            1)                                                                              .000                                                                             2)                                                                              .684                                                                             3)                                                                              .000                                                                             4)                                                                              .000                                                                              5)                                                                              .000                                      Imaging Magnification β.sub.K of Lens Units at Wide-angle End (28.8      mm) in                                                                        Second Embodiment                                                             R  .000                                                                              ANG                                                                              .000                                                                             1)                                                                              .000                                                                             2)                                                                              -.282                                                                            3)                                                                              -.847                                                                            4)                                                                              10.073                                                                            5)                                                                              .155                                      R  10.000                                                                            ANG                                                                              1.459                                                                            1)                                                                              -.008                                                                            2)                                                                              -.278                                                                            3)                                                                              -.847                                                                            4)                                                                              10.073                                                                            5)                                                                              .155                                      R  5.000                                                                             ANG                                                                              2.542                                                                            1)                                                                              -.016                                                                            2)                                                                              -.275                                                                            3)                                                                              -.847                                                                            4)                                                                              10.073                                                                            5)                                                                              .155                                      R  3.000                                                                             ANG                                                                              3.592                                                                            1)                                                                              -.027                                                                            2)                                                                              -.270                                                                            3)                                                                              -.847                                                                            4)                                                                              10.073                                                                            5)                                                                              .155                                      R  2.000                                                                             ANG                                                                              4.609                                                                            1)                                                                              -.042                                                                            2)                                                                              -.264                                                                            3)                                                                              -.847                                                                            4)                                                                              10.073                                                                            5)                                                                              .155                                      R  1.500                                                                             ANG                                                                              5.424                                                                            1)                                                                              -.059                                                                            2)                                                                              -.258                                                                            3)                                                                              -.847                                                                            4)                                                                              10.073                                                                            5)                                                                              .155                                      R  1.000                                                                             ANG                                                                              6.719                                                                            1)                                                                              -.094                                                                            2)                                                                              -.245                                                                            3)                                                                              -.847                                                                            4)                                                                              10.073                                                                            5)                                                                              .155                                      R  .800                                                                              ANG                                                                              7.500                                                                            1)                                                                              -.125                                                                            2)                                                                              -.235                                                                            3)                                                                              -.847                                                                            4)                                                                              10.073                                                                            5)                                                                              .155                                      Conversion Coefficient γ.sub.x Associated With Direction of Optical     Axis at                                                                       Wide-angle End (28.8 mm) in Second Embodiment                                 R  .000                                                                              ANG                                                                              .000                                                                             1)                                                                              .000                                                                             2)                                                                              1.614                                                                            3)                                                                              .000                                                                             4)                                                                              .000                                                                              5)                                                                              .000                                      R  10.000                                                                            ANG                                                                              1.459                                                                            1)                                                                              .000                                                                             2)                                                                              1.617                                                                            3)                                                                              .000                                                                             4)                                                                              .000                                                                              5)                                                                              .000                                      R  5.000                                                                             ANG                                                                              2.542                                                                            1)                                                                              .000                                                                             2)                                                                              1.621                                                                            3)                                                                              .000                                                                             4)                                                                              .000                                                                              5)                                                                              .000                                      R  3.000                                                                             ANG                                                                              3.592                                                                            1)                                                                              .000                                                                             2)                                                                              1.625                                                                            3)                                                                              .000                                                                             4)                                                                              .000                                                                              5)                                                                              .000                                      R  2.000                                                                             ANG                                                                              4.609                                                                            1)                                                                              .000                                                                             2)                                                                              1.631                                                                            3)                                                                              .000                                                                             4)                                                                              .000                                                                              5)                                                                              .000                                      R  1.500                                                                             ANG                                                                              5.424                                                                            1)                                                                              .000                                                                             2)                                                                              1.636                                                                            3)                                                                              .000                                                                             4)                                                                              .000                                                                              5)                                                                              .000                                      R  1.000                                                                             ANG                                                                              6.719                                                                            1)                                                                              .000                                                                             2)                                                                              1.648                                                                            3)                                                                              .000                                                                             4)                                                                              .000                                                                              5)                                                                              .000                                      R  .800                                                                              ANG                                                                              7.500                                                                            1)                                                                              .000                                                                             2)                                                                              1.656                                                                            3)                                                                              .000                                                                             4)                                                                              .000                                                                              5)                                                                              .000                                      Slope dx/da of Focus Cam at Wide-ang1e End (28.8 mm) in Second                Embodiment                                                                    R  .000                                                                              ANG                                                                              .000                                                                             1)                                                                              .000                                                                             2)                                                                              .033                                                                             3)                                                                              .000                                                                             4)                                                                              .000                                                                              5)                                                                              .000                                      R  10.000                                                                            ANG                                                                              1.459                                                                            1)                                                                              .000                                                                             2)                                                                              .041                                                                             3)                                                                              .000                                                                             4)                                                                              .000                                                                              5)                                                                              .000                                      R  5.000                                                                             ANG                                                                              2.542                                                                            1)                                                                              .000                                                                             2)                                                                              .057                                                                             3)                                                                              .000                                                                             4)                                                                              .000                                                                              5)                                                                              .000                                      R  3.000                                                                             ANG                                                                              3.592                                                                            1)                                                                              .000                                                                             2)                                                                              .077                                                                             3)                                                                              .000                                                                             4)                                                                              .000                                                                              5)                                                                              .000                                      R  2.000                                                                             ANG                                                                              4.609                                                                            1)                                                                              .000                                                                             2)                                                                              .100                                                                             3)                                                                              .000                                                                             4)                                                                              .000                                                                              5)                                                                              .000                                      R  1.500                                                                             ANG                                                                              5.424                                                                            1)                                                                              .000                                                                             2)                                                                              .122                                                                             3)                                                                              .000                                                                             4)                                                                              .000                                                                              5)                                                                              .000                                      R  1.000                                                                             ANG                                                                              6.719                                                                            1)                                                                              .000                                                                             2)                                                                              .168                                                                             3)                                                                              .000                                                                             4)                                                                              .000                                                                              5)                                                                              .000                                      R  .800                                                                              ANG                                                                              7.500                                                                            1)                                                                              .000                                                                             2)                                                                              .200                                                                             3)                                                                              .000                                                                             4)                                                                              .000                                                                              5)                                                                              .000                                      Conversion Coefficient γ.sub.a Associated With Direction of             Rotation at                                                                   Wide-angle End (28.8 mm) in Second Embodiment                                 R  .000                                                                              ANG                                                                              .000                                                                             1)                                                                              .000                                                                             2)                                                                              .053                                                                             3)                                                                              .000                                                                             4)                                                                              .000                                                                              5)                                                                              .000                                      R  10.000                                                                            ANG                                                                              1.459                                                                            1)                                                                              .000                                                                             2)                                                                              .066                                                                             3)                                                                              .000                                                                             4)                                                                              .000                                                                              5)                                                                              .000                                      R  5.000                                                                             ANG                                                                              2.542                                                                            1)                                                                              .000                                                                             2)                                                                              .092                                                                             3)                                                                              .000                                                                             4)                                                                              .000                                                                              5)                                                                              .000                                      R  3.000                                                                             ANG                                                                              3.592                                                                            1)                                                                              .000                                                                             2)                                                                              .125                                                                             3)                                                                              .000                                                                             4)                                                                              .000                                                                              5)                                                                              .000                                      R  2.000                                                                             ANG                                                                              4.609                                                                            1)                                                                              .000                                                                             2)                                                                              .163                                                                             3)                                                                              .000                                                                             4)                                                                              .000                                                                              5)                                                                              .000                                      R  1.500                                                                             ANG                                                                              5.424                                                                            1)                                                                              .000                                                                             2)                                                                              .200                                                                             3)                                                                              .000                                                                             4)                                                                              .000                                                                              5)                                                                              .000                                      R  1.000                                                                             ANG                                                                              6.719                                                                            1)                                                                              .000                                                                             2)                                                                              .277                                                                             3)                                                                              .000                                                                             4)                                                                              .000                                                                              5)                                                                              .000                                      R  .800                                                                              ANG                                                                              7.500                                                                            1)                                                                              .000                                                                             2)                                                                              .331                                                                             3)                                                                              .000                                                                             4)                                                                              .000                                                                              5)                                                                              .000                                      __________________________________________________________________________     Condition Corresponding Values: γ.sub.xR /γ.sub.xO = 1.03,        γ.sub.aR /γ.sub.aO = 6.25                                    

                                      TABLE 22                                    __________________________________________________________________________    Amount DX (mm) of Movement for Focusing in Direction of Optical Axis at       Middle Position (70.0 mm) in Second Embodiment                                R .000                                                                              ANG                                                                              .000                                                                             1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                              4)                                                                              .000                                                                              5)                                                                              .000                                      R 10.000                                                                            ANG                                                                              1.467                                                                            1)                                                                              .000                                                                             2)                                                                              .160                                                                             3)                                                                              .000                                                                              4)                                                                              .000                                                                              5)                                                                              .000                                      R 5.000                                                                             ANG                                                                              2.529                                                                            1)                                                                              .000                                                                             2)                                                                              .318                                                                             3)                                                                              .000                                                                              4)                                                                              .000                                                                              5)                                                                              .000                                      R 3.000                                                                             ANG                                                                              3.605                                                                            1)                                                                              .000                                                                             2)                                                                              .523                                                                             3)                                                                              .000                                                                              4)                                                                              .000                                                                              5)                                                                              .000                                      R 2.000                                                                             ANG                                                                              4.651                                                                            1)                                                                              .000                                                                             2)                                                                              .774                                                                             3)                                                                              .000                                                                              4)                                                                              .000                                                                              5)                                                                              .000                                      R 1.500                                                                             ANG                                                                              5.475                                                                            1)                                                                              .000                                                                             2)                                                                              1.018                                                                            3)                                                                              .000                                                                              4)                                                                              .000                                                                              5)                                                                              .000                                      R 1.000                                                                             ANG                                                                              6.738                                                                            1)                                                                              .000                                                                             2)                                                                              1.491                                                                            3)                                                                              .000                                                                              4)                                                                              .000                                                                              5)                                                                              .000                                      R .800                                                                              ANG                                                                              7.500                                                                            1)                                                                              .000                                                                             2)                                                                              1.835                                                                            3)                                                                              .000                                                                              4)                                                                              .000                                                                              5)                                                                              .000                                      Imaging Magnification β.sub.K of Lens Units at Middle Position (70.0     mm) in Second Embodiment                                                      R .000                                                                              ANG                                                                              .000                                                                             1)                                                                              .000                                                                             2)                                                                              -.462                                                                            3)                                                                              -1.216                                                                            4)                                                                              91.883                                                                            5)                                                                              .018                                      R 10.000                                                                            ANG                                                                              1.467                                                                            1)                                                                              -.008                                                                            2)                                                                              -.451                                                                            3)                                                                              -1.216                                                                            4)                                                                              91.883                                                                            5)                                                                              .018                                      R 5.000                                                                             ANG                                                                              2.529                                                                            1)                                                                              -.016                                                                            2)                                                                              -.441                                                                            3)                                                                              -1.216                                                                            4)                                                                              91.883                                                                            5)                                                                              .018                                      R 3.000                                                                             ANG                                                                              3.605                                                                            1)                                                                              -.028                                                                            2)                                                                              -.427                                                                            3)                                                                              -1.216                                                                            4)                                                                              91.883                                                                            5)                                                                              .018                                      R 2.000                                                                             ANG                                                                              4.651                                                                            1)                                                                              -.043                                                                            2)                                                                              -.410                                                                            3)                                                                              -1.216                                                                            4)                                                                              91.883                                                                            5)                                                                              .018                                      R 1.500                                                                             ANG                                                                              5.475                                                                            1)                                                                              -.059                                                                            2)                                                                              -.393                                                                            3)                                                                              -1.216                                                                            4)                                                                              91.883                                                                            5)                                                                              .018                                      R 1.000                                                                             ANG                                                                              6.738                                                                            1)                                                                              -.096                                                                            2)                                                                              -.361                                                                            3)                                                                              -1.216                                                                            4)                                                                              91.883                                                                            5)                                                                              .018                                      R .800                                                                              ANG                                                                              7.500                                                                            1)                                                                              -.129                                                                            2)                                                                              -.338                                                                            3)                                                                              -1.216                                                                            4)                                                                              91.883                                                                            5)                                                                              .018                                      Conversion Coefficient γ.sub.x Associated With Direction of Optical     Axis at                                                                       Middle Position (70.0 mm) in Second Embodiment                                R .000                                                                              ANG                                                                              .000                                                                             1)                                                                              .000                                                                             2)                                                                              3.024                                                                            3)                                                                              .000                                                                              4)                                                                              .000                                                                              5)                                                                              .000                                      R 10.000                                                                            ANG                                                                              1.467                                                                            1)                                                                              .000                                                                             2)                                                                              3.062                                                                            3)                                                                              .000                                                                              4)                                                                              .000                                                                              5)                                                                              .000                                      R 5.000                                                                             ANG                                                                              2.529                                                                            1)                                                                              .000                                                                             2)                                                                              3.099                                                                            3)                                                                              .000                                                                              4)                                                                              .000                                                                              5)                                                                              .000                                      R 3.000                                                                             ANG                                                                              3.605                                                                            1)                                                                              .000                                                                             2)                                                                              3.145                                                                            3)                                                                              .000                                                                              4)                                                                              .000                                                                              5)                                                                              .000                                      R 2.000                                                                             ANG                                                                              4.651                                                                            1)                                                                              .000                                                                             2)                                                                              3.200                                                                            3)                                                                              .000                                                                              4)                                                                              .000                                                                              5)                                                                              .000                                      R 1.500                                                                             ANG                                                                              5.475                                                                            1)                                                                              .000                                                                             2)                                                                              3.251                                                                            3)                                                                              .000                                                                              4)                                                                              .000                                                                              5)                                                                              .000                                      R 1.000                                                                             ANG                                                                              6.738                                                                            1)                                                                              .000                                                                             2)                                                                              3.345                                                                            3)                                                                              .000                                                                              4)                                                                              .000                                                                              5)                                                                              .000                                      R .800                                                                              ANG                                                                              7.500                                                                            1)                                                                              .000                                                                             2)                                                                              3.408                                                                            3)                                                                              .000                                                                              4)                                                                              .000                                                                              5)                                                                              .000                                      Slope dx/da of Focus Cam at Middle Position (70.0 mm) in Second               Embodiment                                                                    R .000                                                                              ANG                                                                              .000                                                                             1)                                                                              .000                                                                             2)                                                                              .090                                                                             3)                                                                              .000                                                                              4)                                                                              .000                                                                              5)                                                                              .000                                      R 10.000                                                                            ANG                                                                              1.467                                                                            1)                                                                              .000                                                                             2)                                                                              .130                                                                             3)                                                                              .000                                                                              4)                                                                              .000                                                                              5)                                                                              .000                                      R 5.000                                                                             ANG                                                                              2.529                                                                            1)                                                                              .000                                                                             2)                                                                              .169                                                                             3)                                                                              .000                                                                              4)                                                                              .000                                                                              5)                                                                              .000                                      R 3.000                                                                             ANG                                                                              3.605                                                                            1)                                                                              .000                                                                             2)                                                                              .213                                                                             3)                                                                              .000                                                                              4)                                                                              .000                                                                              5)                                                                              .000                                      R 2.000                                                                             ANG                                                                              4.651                                                                            1)                                                                              .000                                                                             2)                                                                              .269                                                                             3)                                                                              .000                                                                              4)                                                                              .000                                                                              5)                                                                              .000                                      R 1.500                                                                             ANG                                                                              5.475                                                                            1)                                                                              .000                                                                             2)                                                                              .325                                                                             3)                                                                              .000                                                                              4)                                                                              .000                                                                              5)                                                                              .000                                      R 1.000                                                                             ANG                                                                              6.738                                                                            1)                                                                              .000                                                                             2)                                                                              .423                                                                             3)                                                                              .000                                                                              4)                                                                              .000                                                                              5)                                                                              .000                                      R .800                                                                              ANG                                                                              7.500                                                                            1)                                                                              .000                                                                             2)                                                                              .478                                                                             3)                                                                              .000                                                                              4)                                                                              .000                                                                              5)                                                                              .000                                      Conversion Coefficient γ.sub.a Associated With Direction of             Rotation at                                                                   Middle Position (70.0 mm) in Second Embodiment                                R .000                                                                              ANG                                                                              .000                                                                             1)                                                                              .000                                                                             2)                                                                              .271                                                                             3)                                                                              .000                                                                              4)                                                                              .000                                                                              5)                                                                              .000                                      R 10.000                                                                            ANG                                                                              1.467                                                                            1)                                                                              .000                                                                             2)                                                                              .398                                                                             3)                                                                              .000                                                                              4)                                                                              .000                                                                              5)                                                                              .000                                      R 5.000                                                                             ANG                                                                              2.529                                                                            1)                                                                              .000                                                                             2)                                                                              .523                                                                             3)                                                                              .000                                                                              4)                                                                              .000                                                                              5)                                                                              .000                                      R 3.000                                                                             ANG                                                                              3.605                                                                            1)                                                                              .000                                                                             2)                                                                              .670                                                                             3)                                                                              .000                                                                              4)                                                                              .000                                                                              5)                                                                              .000                                      R 2.000                                                                             ANG                                                                              4.651                                                                            1)                                                                              .000                                                                             2)                                                                              .860                                                                             3)                                                                              .000                                                                              4)                                                                              .000                                                                              5)                                                                              .000                                      R 1.500                                                                             ANG                                                                              5.475                                                                            1)                                                                              .000                                                                             2)                                                                              1.058                                                                            3)                                                                              .000                                                                              4)                                                                              .000                                                                              5)                                                                              .000                                      R 1.000                                                                             ANG                                                                              6.738                                                                            1)                                                                              .000                                                                             2)                                                                              1.416                                                                            3)                                                                              .000                                                                              4)                                                                              .000                                                                              5)                                                                              .000                                      R .800                                                                              ANG                                                                              7.500                                                                            1)                                                                              .000                                                                             2)                                                                              1.629                                                                            3)                                                                              .000                                                                              4)                                                                              .000                                                                              5)                                                                              .000                                      __________________________________________________________________________     Condition Corresponding Values: γ.sub.xR /γ.sub.xO = 1.13,        γ.sub.aR /γ.sub.aO = 6.01                                    

                                      TABLE 23                                    __________________________________________________________________________    Amount DX (mm) of Movement for Focusing in Direction of Optical Axis          at Telephoto End (131.0 mm) in Second Embodiment                              R .000                                                                              ANG                                                                              .000                                                                              1)                                                                              .000                                                                             2)                                                                              .000                                                                             3)                                                                              .000                                                                              4)                                                                              .000                                                                              5)                                                                              .000                                     R 10.000                                                                            ANG                                                                              1.504                                                                             1)                                                                              .000                                                                             2)                                                                              .614                                                                             3)                                                                              .000                                                                              4)                                                                              .000                                                                              5)                                                                              .000                                     R 5.000                                                                             ANG                                                                              2.542                                                                             1)                                                                              .000                                                                             2)                                                                              1.131                                                                            3)                                                                              .000                                                                              4)                                                                              .000                                                                              5)                                                                              .000                                     R 3.000                                                                             ANG                                                                              3.592                                                                             1)                                                                              .000                                                                             2)                                                                              1.725                                                                            3)                                                                              .000                                                                              4)                                                                              .000                                                                              5)                                                                              .000                                     R 2.000                                                                             ANG                                                                              4.609                                                                             1)                                                                              .000                                                                             2)                                                                              2.362                                                                            3)                                                                              .000                                                                              4)                                                                              .000                                                                              5)                                                                              .000                                     R 1.500                                                                             ANG                                                                              5.424                                                                             1)                                                                              .000                                                                             2)                                                                              2.920                                                                            3)                                                                              .000                                                                              4)                                                                              .000                                                                              5)                                                                              .000                                     R 1.000                                                                             ANG                                                                              6.719                                                                             1)                                                                              .000                                                                             2)                                                                              3.879                                                                            3)                                                                              .000                                                                              4)                                                                              .000                                                                              5)                                                                              .000                                     R .800                                                                              ANG                                                                              7.500                                                                             1)                                                                              .000                                                                             2)                                                                              4.505                                                                            3)                                                                              .000                                                                              4)                                                                              .000                                                                              5)                                                                              .000                                     Imaging Magnification β.sub.K of Lens Units                              at Telephoto End (131.0 mm) in Second Embodiment                              R .000                                                                              ANG                                                                              .000                                                                              1)                                                                              .000                                                                             2)                                                                              -.730                                                                            3)                                                                              -1.407                                                                            4)                                                                              -29.909                                                                           5)                                                                              -.055                                    R 10.000                                                                            ANG                                                                              1.504                                                                             1)                                                                              -.008                                                                            2)                                                                              -.688                                                                            3)                                                                              -1.407                                                                            4)                                                                              -29.909                                                                           5)                                                                              -.055                                    R 5.000                                                                             ANG                                                                              2.542                                                                             1)                                                                              -.016                                                                            2)                                                                              -.653                                                                            3)                                                                              -1.407                                                                            4)                                                                              -29.909                                                                           5)                                                                              -.055                                    R 3.000                                                                             ANG                                                                              3.592                                                                             1)                                                                              -.028                                                                            2)                                                                              -.612                                                                            3)                                                                              -1.407                                                                            4)                                                                              -29.909                                                                           5)                                                                              -.055                                    R 2.000                                                                             ANG                                                                              4.609                                                                             1)                                                                              -.043                                                                            2)                                                                              -.569                                                                            3)                                                                              -1.407                                                                            4)                                                                              -29.909                                                                           5)                                                                              -.055                                    R 1.500                                                                             ANG                                                                              5.424                                                                             1)                                                                              -.060                                                                            2)                                                                              -.531                                                                            3)                                                                              -1.407                                                                            4)                                                                              -29.909                                                                           5)                                                                              -.055                                    R 1.000                                                                             ANG                                                                              6.719                                                                             1)                                                                              -.098                                                                            2)                                                                              -.466                                                                            3)                                                                              -1.407                                                                            4)                                                                              -29.909                                                                           5)                                                                              -.055                                    R .800                                                                              ANG                                                                              7.500                                                                             1)                                                                              -.131                                                                            2)                                                                              -.423                                                                            3)                                                                              -1.407                                                                            4)                                                                              -29.909                                                                           5)                                                                              -.055                                    Conversion Coefficient γ.sub.x Associated With Direction of Optical     Axis                                                                          at Telephoto End (131.0 mm) in Second Embodiment                              R .000                                                                              ANG                                                                              .000                                                                              1)                                                                              .000                                                                             2)                                                                              2.528                                                                            3)                                                                              .000                                                                              4)                                                                              .000                                                                              5)                                                                              .000                                     R 10.000                                                                            ANG                                                                              1.504                                                                             1)                                                                              .000                                                                             2)                                                                              2.848                                                                            3)                                                                              .000                                                                              4)                                                                              .000                                                                              5)                                                                              .000                                     R 5.000                                                                             ANG                                                                              2.542                                                                             1)                                                                              .000                                                                             2)                                                                              3.104                                                                            3)                                                                              .000                                                                              4)                                                                              .000                                                                              5)                                                                              .000                                     R 3.000                                                                             ANG                                                                              3.592                                                                             1)                                                                              .000                                                                             2)                                                                              3.380                                                                            3)                                                                              .000                                                                              4)                                                                              .000                                                                              5)                                                                              .000                                     R 2.000                                                                             ANG                                                                              4.609                                                                             1)                                                                              .000                                                                             2)                                                                              3.657                                                                            3)                                                                              .000                                                                              4)                                                                              .000                                                                              5)                                                                              .000                                     R 1.500                                                                             ANG                                                                              5.424                                                                             1)                                                                              .000                                                                             2)                                                                              3.883                                                                            3)                                                                              .000                                                                              4)                                                                              .000                                                                              5)                                                                              .000                                     R 1.000                                                                             ANG                                                                              6.719                                                                             1)                                                                              .000                                                                             2)                                                                              4.235                                                                            3)                                                                              .000                                                                              4)                                                                              .000                                                                              5)                                                                              .000                                     R .800                                                                              ANG                                                                              7.500                                                                             1)                                                                              .000                                                                             2)                                                                              4.439                                                                            3)                                                                              .000                                                                              4)                                                                              .000                                                                              5)                                                                              .000                                     Slope dx/da of Focus Cam                                                      at Telephoto End (131.0 mm) in Second Embodiment                              R .000                                                                              ANG                                                                              .000                                                                              1)                                                                              .000                                                                             2)                                                                              .350                                                                             3)                                                                              .000                                                                              4)                                                                              .000                                                                              5)                                                                              .000                                     R 10.000                                                                            ANG                                                                              1.504                                                                             1)                                                                              .000                                                                             2)                                                                              .464                                                                             3)                                                                              .000                                                                              4)                                                                              .000                                                                              5)                                                                              .000                                     R 5.000                                                                             ANG                                                                              2.542                                                                             1)                                                                              .000                                                                             2)                                                                              .533                                                                             3)                                                                              .000                                                                              4)                                                                              .000                                                                              5)                                                                              .000                                     R 3.000                                                                             ANG                                                                              3.592                                                                             1)                                                                              .000                                                                             2)                                                                              .596                                                                             3)                                                                              .000                                                                              4)                                                                              .000                                                                              5)                                                                              .000                                     R 2.000                                                                             ANG                                                                              4.609                                                                             1)                                                                              .000                                                                             2)                                                                              .659                                                                             3)                                                                              .000                                                                              4)                                                                              .000                                                                              5)                                                                              .000                                     R 1.500                                                                             ANG                                                                              5.424                                                                             1)                                                                              .000                                                                             2)                                                                              .708                                                                             3)                                                                              .000                                                                              4)                                                                              .000                                                                              5)                                                                              .000                                     R 1.000                                                                             ANG                                                                              6.719                                                                             1)                                                                              .000                                                                             2)                                                                              .771                                                                             3)                                                                              .000                                                                              4)                                                                              .000                                                                              5)                                                                              .000                                     R .800                                                                              ANG                                                                              7.500                                                                             1)                                                                              .000                                                                             2)                                                                              .843                                                                             3)                                                                              .000                                                                              4)                                                                              .000                                                                              5)                                                                              .000                                     Conversion Coefficient γ.sub.a Associated With Direction of             Rotation                                                                      at Telephoto End (131.0 mm) in Second Embodiment                              R .000                                                                              ANG                                                                              .000                                                                              1)                                                                              .000                                                                             2)                                                                              .885                                                                             3)                                                                              .000                                                                              4)                                                                              .000                                                                              5)                                                                              .000                                     R 10.000                                                                            ANG                                                                              1.504                                                                             1)                                                                              .000                                                                             2)                                                                              1.320                                                                            3)                                                                              .000                                                                              4)                                                                              .000                                                                              5)                                                                              .000                                     R 5.000                                                                             ANG                                                                              2.542                                                                             1)                                                                              .000                                                                             2)                                                                              1.655                                                                            3)                                                                              .000                                                                              4)                                                                              .000                                                                              5)                                                                              .000                                     R 3.000                                                                             ANG                                                                              3.592                                                                             1)                                                                              .000                                                                             2)                                                                              2.014                                                                            3)                                                                              .000                                                                              4)                                                                              .000                                                                              5)                                                                              .000                                     R 2.000                                                                             ANG                                                                              4.609                                                                             1)                                                                              .000                                                                             2)                                                                              2.411                                                                            3)                                                                              .000                                                                              4)                                                                              .000                                                                              5)                                                                              .000                                     R 1.500                                                                             ANG                                                                              5.424                                                                             1)                                                                              .000                                                                             2)                                                                              2.750                                                                            3)                                                                              .000                                                                              4)                                                                              .000                                                                              5)                                                                              .000                                     R 1.000                                                                             ANG                                                                              6.719                                                                             1)                                                                              .000                                                                             2)                                                                              3.266                                                                            3)                                                                              .000                                                                              4)                                                                              .000                                                                              5)                                                                              .000                                     R .800                                                                              ANG                                                                              7.500                                                                             1)                                                                              .000                                                                             2)                                                                              3.742                                                                            3)                                                                              .000                                                                              4)                                                                              .000                                                                              5)                                                                              .000                                     __________________________________________________________________________     Condition Corresponding Values: γ.sub.xR /γ.sub.xO = 1.76,        γ.sub.aR /γ.sub.aO = 4.23                                    

As can be seen from Tables 21, 22, and 23, at each focal length, theconversion coefficient γ_(x) associated with the direction of theoptical axis and the slope (dx/da) of the focus cam increase as thephotographing distance becomes closer to the closest distance.Therefore, the degree of change in the conversion coefficient γ_(a)associated with the direction of rotation, which is defined as theproduct of the conversion coefficient γ_(x) and the slope (dx/da) of thefocus cam, increases, but becomes smaller than that in the case wherethe rotation amount ration (a_(F) /a_(Z)) is set to be 1.0 similarly tothe embodiment of Japanese Patent Application No. 5-142475.

From Tables 21, 22, and 23, the rate of change, from the infinityin-focus position to the closest in-focus position, of the conversioncoefficient γ_(a) associated with the direction of rotation is ×6.25 atthe wide-angle end (F=28.8), ×6.01 at the middle position (F=70.0), and×4.23 at the telephoto end (F=131.0). When the number N of divisions ofthe focus range upon a change in conversion coefficient γ_(a) in thesecond embodiment is calculated using formula (a), and is compared withthat in the case where the rotation amount ration (a_(F) /a_(Z)) is setto be 1.0 similarly to the embodiment of Japanese Patent ApplicationLaid-Open No. 5-142475, the numbers N_(W), N_(M), and N_(T) of divisionsat the wide-angle end, middle position, and telephoto end respectivelyhave the following values:

In Case Where Rotation Amount Ratio (a_(F) /a_(Z)) Is Set To Be 1.0

N_(W) >13.0 N_(M) >12.6 N_(T) >10.7

Second Embodiment

N_(W) >10.0 N_(M) >9.8 N_(T) >7.9

Therefore, as can be seen from the above comparison with the case wherethe rotation amount ratio (a_(F) /a_(Z)) is set to be 1.0 similarly tothe embodiment of Japanese Patent Application Laid-Open No. 5-142475,the values of the numbers N of divisions become small.

As described above, in the second embodiment as well, since the rate ofchange of the conversion coefficient γ_(a) associated with the directionof rotation is smaller than that in the case where the rotation amountration (a_(F) /a_(Z)) is set to be 1.0 similarly to the embodiment ofJapanese Patent Application Laid-Open No. 5-142475, the number of dataof the conversion coefficient γ_(a) and the correction coefficient μ canbe reduced, and the storage capacity can be suppressed.

Tables 24, 25, and 26 summarize the calculation results of theconversion coefficient K_(a) and the correction coefficient μ at thewide-angle end (F=28.8), middle position (F=70.0), and telephoto end(F=131.0) according to the second embodiment. The arrangements of thetables and reference symbols are the same as those in the firstembodiment. The position of the focusing lens in the first pair in theupper two tables in each of Tables 24, 25, and 26, i.e., in the thirdand fourth columns is (R, ANGLE)=(0.0, 0.0), and it indicates that thisposition corresponds to the infinity corresponding position. Similarly,the position of the focusing lens in the fourth pair in the lower twotables in each of Tables 24, 25, and 26, i.e., in the ninth and tenthcolumns is (R, ANGLE)=(0.8, 7.5), and it indicates that this positioncorresponds to the closest in-focus (R=0.80 m) corresponding position.

                                      TABLE 24                                    __________________________________________________________________________    Conversion Coefficients K.sub.a : (rs), γ.sub.a : (r) Associated        with Direction of Rotation                                                    and Correction Coefficient μ: (l) at Wide-angle End (28.8 mm) of           Second Embodiment                                                             f = 28.8 mm                                                                   __________________________________________________________________________           (R,ANGLE) =                                                                   .000                                                                             .000 10.000                                                                            1.459                                                                            5.000                                                                              2.542                                                                            3.000                                                                              3.592                                      POS                                                                              R   r  rs   r   rs r    rs r    rs                                         __________________________________________________________________________    1  .000                                                                              .053                                                                             .000     .057    .066    .078                                       2  10.000 .057 .066                                                                              .000    .078    .092                                       3  5.000  .066     .078                                                                             .092 .000    .108                                       4  3.000  .079     .094    .109                                                                             .125 .000                                       5  2.000  .094     .110    .127    .143                                       6  1.500  .108     .126    .143    .162                                       7  1.000  .135     .156    .175    .196                                       8  .800   .155     .178    .199    .221                                       __________________________________________________________________________    POS                                                                              R   bf l    bf  l  bf   l  bf   l                                          __________________________________________________________________________    1  .000                                                                              .00                                                                              .00  -.08                                                                              -.62                                                                             -.17 -.57                                                                             -.28 -.74                                       2  10.000                                                                            .08                                                                              -.97 .00 .00                                                                              -.08 -.53                                                                             -.20 -.76                                       3  5.000                                                                             .17                                                                              -.66 .08 -.45                                                                             .00  .00                                                                              -.11 -.86                                       4  3.000                                                                             .28                                                                              -.57 .20 -.47                                                                             .11  -.63                                                                             .00  .00                                        5  2.000                                                                             .43                                                                              -.55 .35 -.51                                                                             .26  -.71                                                                             .15  -.97                                       6  1.500                                                                             .59                                                                              -.56 .50 -.55                                                                             .41  -.75                                                                             .30  -.99                                       7  1.000                                                                             .91                                                                              -.58 .82 -.60                                                                             .73  -.82                                                                             .61  -1.07                                      8  .800                                                                              1.17                                                                             -.60 1.08                                                                              -.63                                                                             .98  -.86                                                                             .86  -1.12                                      __________________________________________________________________________           (R,ANGLE) =                                                                   2.000                                                                            4.609                                                                              1.500                                                                             5.424                                                                            1.000                                                                              6.719                                                                            .800 7.500                                      POS                                                                              R   r  rs   r   rs r    rs r    rs                                         __________________________________________________________________________    1  .000   .091     .104    .127    .143                                       2  10.000 .108     .122    .147    .165                                       3  5.000  .124     .139    .166    .185                                       4  3.000  .142     .158    .187    .207                                       5  2.000                                                                             .163                                                                             .000     .181    .211    .233                                       6  1.500  .183 .200                                                                              .000    .233    .256                                       7  1.000  .219     .238                                                                             .277 .000    .301                                       8  .800   .245     .267    .307                                                                             .331 .000                                       __________________________________________________________________________    POS                                                                              R   bf l    bf  l  bf   l  bf   l                                          __________________________________________________________________________    1  .000                                                                              -.42                                                                             -.95 -.56                                                                              -1.17                                                                            -.85 -1.57                                                                            -1.07                                                                              -1.89                                      2  10.000                                                                            -.34                                                                             -1.00                                                                              -.48                                                                              -1.23                                                                            -.77 -1.65                                                                            -1.00                                                                              -1.98                                      3  5.000                                                                             -.26                                                                             -1.07                                                                              -.40                                                                              -1.31                                                                            -.69 -1.74                                                                            -.92 -2.08                                      4  3.000                                                                             -.14                                                                             -1.11                                                                              -.29                                                                              -1.38                                                                            -.59 -1.81                                                                            -.81 -2.17                                      5  2.000                                                                             .00                                                                              .00  -.15                                                                              -1.49                                                                            -.45 -1.89                                                                            -.67 -2.28                                      6  1.500                                                                             .15                                                                              -1.23                                                                              .00 .00                                                                              -.30 -1.92                                                                            -.53 -2.36                                      7  1.000                                                                             .46                                                                              -1.35                                                                              .31 -1.63                                                                            .00  .00                                                                              -.24 -2.64                                      8  .800                                                                              .71                                                                              -1.41                                                                              .55 -1.67                                                                            .24  -2.21                                                                            .00  .00                                        __________________________________________________________________________     Condition Corresponding Values: K.sub.aO /γ.sub.aO = 2.92, K.sub.aR     /γ.sub.aR = 0.43                                                   

                                      TABLE 25                                    __________________________________________________________________________    Conversion Coefficients K.sub.a : (rs), γ.sub.a : (r) Associated        with Direction of Rotation                                                    and Correction Coefficient μ: (l) at Middle Position (70.0 mm) of          Second Embodiment                                                             f = 70.0 mm                                                                   __________________________________________________________________________           (R,ANGLE) =                                                                   .000                                                                             .000 10.000                                                                            1.467                                                                            5.000                                                                              2.529                                                                             3.000                                                                             3.605                                      POS                                                                              R   r  rs   r   rs r    rs  r   rs                                         __________________________________________________________________________    1  .000                                                                              .272                                                                             .000     .328    .374    .427                                       2  10.000 .338 .398                                                                              .000    .450    .510                                       3  5.000  .396     .463                                                                             .523 .000    .585                                       4  3.000  .470     .545    .607                                                                              .670                                                                              .000                                       5  2.000  .557     .639    .706    .778                                       6  1.500  .644     .733    .806    .886                                       7  1.000  .817     .922    1.007   1.101                                      8  .800   .947     1.062   1.154   1.255                                      __________________________________________________________________________    POS                                                                              R   bf l    bf  l  bf   l   bf  l                                          __________________________________________________________________________    1  .000                                                                              .00                                                                              .00  -.48                                                                              -2.74                                                                            -.95 -3.31                                                                             -1.54                                                                             -4.24                                      2  10.000                                                                            .50                                                                              -2.03                                                                              .00 .00                                                                              -.48 -3.42                                                                             -1.09                                                                             -4.54                                      3  5.000                                                                             1.00                                                                             -2.18                                                                              .49 -2.98                                                                            .00  .00 -.63                                                                              -4.93                                      4  3.000                                                                             1.70                                                                             -2.32                                                                              1.16                                                                              -3.15                                                                            .65  -4.05                                                                             .00 .00                                        5  2.000                                                                             2.59                                                                             -2.46                                                                              2.03                                                                              -3.35                                                                            1.50 -4.28                                                                             .81 -5.08                                      6  1.500                                                                             3.52                                                                             -2.57                                                                              2.94                                                                              -3.48                                                                            2.38 -4.39                                                                             1.66                                                                              -5.15                                      7  1.000                                                                             5.50                                                                             -2.74                                                                              4.86                                                                              -3.69                                                                            4.24 -4.58                                                                             3.45                                                                              -5.37                                      8  .800                                                                              7.10                                                                             -2.86                                                                              6.40                                                                              -3.84                                                                            5.74 -4.76                                                                             4.89                                                                              -5.61                                      __________________________________________________________________________           (R,ANGLE) =                                                                   2.000                                                                            4.651                                                                              1.500                                                                             5.475                                                                            1.000                                                                              6.738                                                                             .800                                                                              7.500                                      POS                                                                              R   r  rs   r   rs r    rs  r   rs                                         __________________________________________________________________________    1  .000   .483     .534    .621    .675                                       2  10.000 .571     .626    .721    .779                                       3  5.000  .649     .709    .811    .872                                       4  3.000  .743     .809    .921    .986                                       5  2.000                                                                             .861                                                                             .000     .934    1.056   1.122                                      6  1.500  .977 1.058                                                                             .000    1.185   1.250                                      7  1.000  1.204    1.292                                                                            1.417                                                                              .000    1.476                                      8  .800   1.363    1.452   1.572                                                                             1.629                                                                             .000                                       __________________________________________________________________________    POS                                                                              R   bf l    bf  l  bf   l   bf  l                                          __________________________________________________________________________    1  .000                                                                              -2.25                                                                            -5.13                                                                              -2.92                                                                             -5.90                                                                            -4.18                                                                              -7.44                                                                             -5.06                                                                             -8.63                                      2  10.000                                                                            -1.82                                                                            -5.40                                                                              -2.51                                                                             -6.15                                                                            -3.80                                                                              -7.74                                                                             -4.70                                                                             -9.01                                      3  5.000                                                                             -1.38                                                                            -5.61                                                                              -2.09                                                                             -6.33                                                                            -3.41                                                                              -7.99                                                                             -4.34                                                                             -9.34                                      4  3.000                                                                             -.78                                                                             -5.67                                                                              -1.51                                                                             -6.44                                                                            -2.89                                                                              -8.25                                                                             -3.84                                                                             -9.72                                      5  2.000                                                                             .00                                                                              .00  -.77                                                                              -6.61                                                                            -2.20                                                                              -8.64                                                                             -3.20                                                                             -10.27                                     6  1.500                                                                             .81                                                                              -5.94                                                                              .00 .00                                                                              -1.50                                                                              -9.13                                                                             -2.53                                                                             -10.88                                     7  1.000                                                                             2.51                                                                             -6.29                                                                              1.63                                                                              -7.36                                                                            .00  .00 -1.13                                                                             -11.98                                     8  .800                                                                              3.88                                                                             -6.65                                                                              2.94                                                                              -7.89                                                                            1.20 -10.94                                                                            .00 .00                                        __________________________________________________________________________     Condition Corresponding Values: K.sub.aO /γ.sub.aO = 3.48, K.sub.aR     /γ.sub.aR = 0.41                                                   

                                      TABLE 26                                    __________________________________________________________________________    Conversion Coefficients K.sub.a : (rs), γ.sub.a : (r) Associated        with Direction of Rotation                                                    and Correction Coefficient μ: (l) at Telephoto End (131.0 mm) of           Second Embodiment                                                             f = 131.0 mm                                                                  __________________________________________________________________________           (R,ANGLE) =                                                                   .000                                                                              .000                                                                              10.000                                                                            1.504                                                                             5.000                                                                             2.542                                                                             3.000                                                                             3.592                                      POS                                                                              R   r   rs  r   rs  r   rs  r   rs                                         __________________________________________________________________________    1  .000                                                                              .884                                                                              .000    1.037   1.132   1.219                                      2  10.000  1.167                                                                             1.321                                                                             .000    1.413   1.495                                      3  5.000   1.413   1.566                                                                             1.654                                                                             .000    1.729                                      4  3.000   1.719   1.869   1.950                                                                             2.017                                                                             .000                                       5  2.000   2.093   2.235   2.307   2.361                                      6  1.500   2.473   2.607   2.668   2.710                                      7  1.000   3.278   3.378   3.403   3.404                                      8  .800    3.951   4.010   3.998   3.957                                      __________________________________________________________________________    POS                                                                              R   bf  l   bf  l   bf  l   bf  l                                          __________________________________________________________________________    1  .000                                                                              .00 .00 -1.56                                                                             -7.24                                                                             -2.88                                                                             -9.12                                                                             -4.38                                                                             -11.08                                     2  10.000                                                                            1.75                                                                              -5.49                                                                             .00 .00 -1.47                                                                             -10.08                                                                            -3.12                                                                             -12.06                                     3  5.000                                                                             3.59                                                                              -6.01                                                                             1.63                                                                              -8.77                                                                             .00 .00 -1.82                                                                             -12.74                                     4  3.000                                                                             6.17                                                                              -6.54                                                                             3.90                                                                              -9.41                                                                             2.05                                                                              -11.42                                                                            .00 .00                                        5  2.000                                                                             9.65                                                                              -7.06                                                                             6.94                                                                              -10.03                                                                            4.77                                                                              -12.07                                                                            2.40                                                                              -14.06                                     6  1.500                                                                             13.42                                                                             -7.46                                                                             10.22                                                                             -10.50                                                                            7.69                                                                              -12.54                                                                            4.97                                                                              -14.44                                     7  1.000                                                                             22.02                                                                             -8.13                                                                             17.61                                                                             -11.31                                                                            14.22                                                                             -13.44                                                                            10.64                                                                             -15.47                                     8  .800                                                                              29.63                                                                             -8.54                                                                             24.04                                                                             -11.81                                                                            19.82                                                                             -13.98                                                                            15.47                                                                             -16.07                                     __________________________________________________________________________           (R,ANGLE) =                                                                   2.000                                                                             4.609                                                                             1.500                                                                             5.424                                                                             1.000                                                                             6.719                                                                             .800                                                                              7.500                                      POS                                                                              R   r   rs  r   rs  r   rs  r   rs                                         __________________________________________________________________________    1  .000    1.295   1.353   1.430   1.472                                      2  10.000  1.564   1.616   1.682   1.716                                      3  5.000   1.792   1.839   1.894   1.921                                      4  3.000   2.070   2.111   2.149   2.167                                      5  2.000                                                                             2.409                                                                             .000    2.440   2.449   2.453                                      6  1.500   2.743                                                                             2.750                                                                             .000    2.729   2.721                                      7  1.000   3.387   3.351                                                                             3.266                                                                             .000    3.255                                      8  .800    3.899   3.832   3.727                                                                             3.740                                                                             .000                                       __________________________________________________________________________    POS                                                                              R   bf  l   bf  l   bf  l   bf  l                                          __________________________________________________________________________    1  .000                                                                              -5.97                                                                             -12.92                                                                            -7.34                                                                             -14.44                                                                            -9.61                                                                             -17.10                                                                            -11.04                                                                            -18.20                                     2  10.000                                                                            -4.86                                                                             -13.85                                                                            -6.33                                                                             -15.36                                                                            -8.77                                                                             -18.09                                                                            -10.29                                                                            -19.02                                     3  5.000                                                                             -3.70                                                                             -14.46                                                                            -5.30                                                                             -15.99                                                                            -7.91                                                                             -18.83                                                                            -9.52                                                                             -19.58                                     4  3.000                                                                             -2.11                                                                             -14.96                                                                            -3.87                                                                             -16.65                                                                            -6.72                                                                             -19.66                                                                            -8.47                                                                             -20.13                                     5  2.000                                                                             .00 .00 -1.99                                                                             -17.62                                                                            -5.17                                                                             -20.67                                                                            -7.09                                                                             -20.61                                     6  1.500                                                                             2.24                                                                              -16.09                                                                            .00 .00 -3.53                                                                             -21.50                                                                            -5.65                                                                             -20.73                                     7  1.000                                                                             7.14                                                                              -17.59                                                                            4.34                                                                              -19.86                                                                            .00 .00 -2.54                                                                             -19.63                                     8  .800                                                                              11.27                                                                             -18.22                                                                            7.96                                                                              -20.22                                                                            2.91                                                                              -20.61                                                                            .00 .00                                        __________________________________________________________________________     Condition Corresponding Values: K.sub.aO /γ.sub.aO = 4.47, K.sub.aR     /γ.sub.aR = 0.39                                                   

The calculation results of the rate of change of K_(a) with respect toγ_(a) at the infinity in-focus arrangement and the closest in-focusarrangement at the wide-angle end, middle position, and telephoto end inthe case where the rotation amount ratio (a_(F) /a_(Z)) is set to be 1.0similarly to the embodiment of Japanese Patent Application Laid-Open No.5-142475 and in the second embodiment of the present invention where therotation amount ratio (a_(F) /a_(Z)) is set to be 0.75 are as follows.

    ______________________________________                                        In Case Where Rotation Amount Ratio (a.sub.F /a.sub.Z) Is Set To Be 1.0                Infinity Arrangement                                                                       Closest Arrangement                                              K.sub.aO /γ.sub.aO                                                                   K.sub.aR /γ.sub.aR                                ______________________________________                                        Wide-angle End                                                                           4.18           0.36                                                (F = 28.8)                                                                    Middle Position                                                                          5.00           0.36                                                (F = 70.0)                                                                    Telephoto End                                                                            6.51           0.35                                                (F = 131.0)                                                                   Second Embodiment                                                             Wide-angle End                                                                           2.92           0.43                                                (F = 28.8)                                                                    Middle Position                                                                          3.48           0.41                                                (F = 70.0)                                                                    Telephoto End                                                                            4.47           0.39                                                (F = 131.0)                                                                   ______________________________________                                    

As described above, in the second embodiment as well, since the rate ofchange of K_(a) with respect to γ_(a) is small as compared to theconventional system, the contribution of the correction term (ΔBf/μ) inK_(a) =γ_(a) (1-ΔBf/μ) can be reduced. For this reason, an error of theconversion coefficient K_(a) calculated based on γ_(a) and μ or an errorfrom the actual lens driving amount Δa obtained when only one pair of aconversion coefficient γ_(a) value and a correction coefficient μ valueare set can be reduced.

Next, in the case where the rotation amount ratio (a_(F) /a_(Z)) is setto be 1.0 similarly to the embodiment of Japanese Patent ApplicationLaid-Open No. 5-142475 and the second embodiment of the presentinvention where the rotation amount ratio (a_(F) /a_(Z)) is set to be0.75, when the lens driving amounts upon focusing from the infinityin-focus lens arrangement to the closest distance object and uponfocusing from the closest in-focus lens arrangement to the infinityobject at the wide-angle end, middle position, and telephoto end arecalculated from Δa=ΔBf/ γ_(a) (1-ΔBf/μ)!, and errors from the actuallens driving amounts are then calculated, the following values areobtained. Note that the value of the correction coefficient μ uponfocusing from the infinity in-focus lens arrangement to the closestdistance object adopts a value at the object distance (POS-5), and thevalue of the correction coefficient μ upon focusing from the closestin-focus lens arrangement to the infinity object adopts a value at theobject distance (POS-4).

    ______________________________________                                        In Case Where Rotation Amount Ration (a.sub.F /a.sub.Z) is set to be 1.0               Infinity Arrangement →                                                              Closest Arrangement →                                     Closest In-focus State                                                                     Infinity In-focus State                                 ______________________________________                                        Wide-angle End                                                                           -8.1%          -21.4%                                              (F = 28.8)                                                                    Middle Position                                                                          -13.3%         -21.9%                                              (F = 70.0)                                                                    Telephoto End                                                                            -15.8%         -22.7%                                              (F = 131.0)                                                                   Second Embodiment                                                             Wide-angle End                                                                           -5.9%          -15.0%                                              (F = 28.8)                                                                    Middle Position                                                                          -10.4%         -13.6%                                              (F = 70.0)                                                                    Telephoto End                                                                            -14.0%         -12.8%                                              (F = 131.0)                                                                   ______________________________________                                    

As described above, in the second embodiment as well, even when only apair of a conversion coefficient γ_(a) value and a correctioncoefficient μ value are set for a given lens arrangement range, an errorbetween the conversion coefficient K_(a) calculated from γ_(a) and μ andthe lens driving amount Δa for focusing becomes small as compared to theconventional system, and focusing can be realized with higher accuracy.

Table 27 summarizes the amount (ANGLE DA) of rotation for focusing uponmanual focusing using the focus cam (the middle table in Table 19) ofthe second embodiment, the amount DX (mm) of movement, in the directionof the optical axis, of the focusing lens unit corresponding to theamount of rotation for focusing, and the displacement amount Bf (mm) ofthe imaging point when the amount (DX) of movement in the direction ofthe optical axis is given.

Note that the arrangement of the table and reference symbols are thesame as those in the first embodiment. The upper table in Table 27summarizes the displacement amount (Bf) of the imaging pointcorresponding to the photographing distances (R=5.0, 3.0, 2.0, 1.5, 1.0,and 0.8 m) in the respective zooming states of the focal lengths(F=28.8, 35.0, 50.0, 70.0, 105.0, and 131.0 mm), and the middle tablesummarizes the values of the amount (ANGLE DA) of rotation for focusingrequired for attaining an optimal in-focus state with respect to therespective photographing distances. The lower table summarizes theamounts (DX) of movement, in the direction of the optical axis, of therespective lens units corresponding to the amount (ANGLE DA) of rotationfor focusing in association with the focal lengths and photographingdistances.

                  TABLE 27                                                        ______________________________________                                        Displacement Amount Bf (mm) of Imaging Point and Amount DX (mm)               of movement for focusing in Second Embodiment                                 ______________________________________                                                              0.80  1.00 1.50 2.00 3.00 5.00                                                m     m    m    m    m    m                             ______________________________________                                        F    28.800  Bf       .000  .000 .000 .000 .000 .000                          F    35.000  Bf       .000  -.004                                                                              -.002                                                                              -.003                                                                              -.002                                                                              -.001                         F    50.000  Bf       .000  .003 -.008                                                                              -.013                                                                              -.014                                                                              -.015                         F    70.000  Bf       .000  .027 .054 .036 .009 -.007                         F    105.000 Bf       .000  -.045                                                                              -.048                                                                              -.027                                                                              .017 .033                          F    131.000 Bf       .000  .000 .000 .000 .000 .000                               ANGLE   DA       7.500 6.719                                                                              5.424                                                                              4.609                                                                              3.592                                                                              2.542                         ______________________________________                                        F   28.800  DX     .000 .684 .000 .000  .000 R   0.80 m                       F   35.000  DX     .000 .831 .000 .000  .000 R   0.80 m                       F   50.000  DX     .000 1.222                                                                              .000 .000  .000 R   0.80 m                       F   70.000  DX     .000 1.835                                                                              .000 .000  .000 R   0.80 m                       F   105.000 DX     .000 3.204                                                                              .000 .000  .000 R   0.80 m                       F   131.000 DX     .000 4.505                                                                              .000 .000  .000 R   0.80 m                       F   28.800  DX     .000 .540 .000 .000  .000 R   1.00 m                       F   35.000  DX     .000 .661 .000 .000  .000 R   1.00 m                       F   50.000  DX     .000 .977 .000 .000  .000 R   1.00 m                       F   70.000  DX     .000 1.483                                                                              .000 .000  .000 R   1.00 m                       F   105.000 DX     .000 2.698                                                                              .000 .000  .000 R   1.00 m                       F   131.000 DX     .000 3.879                                                                              .000 .000  .000 R   1.00 m                       F   28.800  DX     .000 .354 .000 .000  .000 R   1.50 m                       F   35.000  DX     .000 .435 .000 .000  .000 R   1.50 m                       F   50.000  DX     .000 .656 .000 .000  .000 R   1.50 m                       F   70.000  DX     .000 1.001                                                                              .000 .000  .000 R   1.50 m                       F   105.000 DX     .000 1.941                                                                              .000 .000  .000 R   1.50 m                       F   131.000 DX     .000 2.920                                                                              .000 .000  .000 R   1.50 m                       F   28.800  DX     .000 .263 .000 .000  .000 R   2.00 m                       F   35.000  DX     .000 .325 .000 .000  .000 R   2.00 m                       F   50.000  DX     .000 .496 .000 .000  .000 R   2.00 m                       F   70.000  DX     .000 .762 .000 .000  .000 R   2.00 m                       F   105.000 DX     .000 1.518                                                                              .000 .000  .000 R   2.00 m                       F   131.000 DX     .000 2.362                                                                              .000 .000  .000 R   2.00 m                       F   28.800  DX     .000 .174 .000 .000  .000 R   3.00 m                       F   35.000  DX     .000 .215 .000 .000  .000 R   3.00 m                       F   50.000  DX     .000 .333 .000 .000  .000 R   3.00 m                       F   70.000  DX     .000 .520 .000 .000  .000 R   3.00 m                       F   105.000 DX     .000 1.053                                                                              .000 .000  .000 R   3.00 m                       F   131.000 DX     .000 1.725                                                                              .000 .000  .000 R   3.00 m                       F   28.800  DX     .000 .104 .000 .000  .000 R   5.00 m                       F   35.000  DX     .000 .129 .000 .000  .000 R   5.00 m                       F   50.000  DX     .000 .203 .000 .000  .000 R   5.00 m                       F   70.000  DX     .000 .320 .000 .000  .000 R   5.00 m                       F   105.000 DX     .000 .653 .000 .000  .000 R   5.00 m                       F   131.000 DX     .000 1.131                                                                              .000 .000  .000 R   5.00 m                       ______________________________________                                    

As can be seen from Table 27, so-called manual focusing can be attainedin the zoom lens according to the second embodiment since thedisplacement amounts of the imaging point at the respective focallengths and photographing distances are very small, and fall within thedepth of focus independently of the zooming state and photographingdistance.

As described above in the embodiments, the present invention can beapplied to zoom lens systems based on various lens unit arrangements orfocusing lens units.

As described above, according to the present invention, in an innerfocusing type zoom lens which is attached to, e.g., an auto-focusingcamera which has focus detection means, storage means, calculationmeans, and the like, the number of data of specific coefficients (e.g.,the conversion coefficient γ_(a) and the correction coefficient μ)required for auto-focusing can be reduced as compared to theconventional system, without making a lens barrel mechanism.Furthermore, an error upon calculation of the lens driving amount of thefocusing lens unit using the stored specific coefficients incorrespondence with the detected defocus amount can be reduced ascompared to the conventional system.

In other words, when the arrangement of the present invention isadopted, since the rate of change of the conversion coefficient γ_(a) isreduced so much as compared to the conventional system, the number ofdata of the conversion coefficient γ_(a), the correction coefficient μ,and the like which are stored for calculating the lens driving amountfor focusing can be reduced, and a cost reduction can be realized interms of the storage capacity.

Furthermore, since the change in conversion coefficient K_(a) to theconversion coefficient γ_(a) becomes small, the contribution of thecorrection term (ΔBf/μ) in K_(a) =γ_(a) (1-ΔBf/μ) can be reduced.

Therefore, an error of the conversion coefficient K_(a) calculated basedon γ_(a) and μ or an error from the actual lens driving amount Δaobtained when only one pair of a conversion coefficient γ_(a) value anda correction coefficient μ value are set for a certain lens arrangementrange can be reduced.

In the present invention, the conversion coefficient γ_(a) at anin-focus point and the conversion coefficient μ which is defined byformula K_(a) =γ_(a) (1-ΔBf/μ) are set to be specific coefficients.Alternatively, a correction coefficient defined by a formula differentfrom the above-mentioned formula may be set. Furthermore, the conversioncoefficient γ_(a) need not always be set in correspondence with thesensitivity (dBf/da) associated with the direction of rotation at anin-focus point. As long as focusing accuracy can be improved, thesensitivity at a point other than the in-focus point and thecorresponding correction coefficient may be set to be specificcoefficients.

Note that the present invention can be applied to various other zoomlens systems based on lens unit arrangements or focusing lens unitsother than those in the above-mentioned embodiments, as a matter ofcourse.

What is claimed is:
 1. A zoom lens system in which a movement locus of afocusing lens unit is defined by synthesizing a focus cam and a zoomcompensation cam so as to achieve an in-focus state by a substantiallyconstant amount of rotation for an identical object distanceindependently of a zooming state upon expression of a predeterminedmovement locus for zooming by an amount of movement, in a direction ofan optical axis, of lens units, and an angle of rotation of a rotatablelens barrel, wherein when ratios (dBf/dx) of an amount dBf ofinfinitesimal movement of an imaging plane to an amount dx ofinfinitesimal movement, in the direction of the optical axis, of saidfocusing lens unit at infinity and closest in-focus points arerespectively represented by γ_(x0) and γ_(xR), amounts of movement, inthe direction of the optical axis, of said focusing lens unit requiredfor focusing from an infinity position to a closest distance position ata wide-angle end and a telephoto end are respectively represented byΔx_(WR) and Δx_(TR), and an amount of rotation of said focusing lensunit on said focus cam corresponding to zooming from the wide-angle endto the telephoto end and an amount of rotation corresponding to focusingfrom an infinity in-focus state to a closest in-focus state arerespectively represented by a_(Z) and a_(F), said zoom lens satisfiesthe following conditional formulas at least at the telephoto end:

    1.00<γ.sub.aR /γ.sub.x0

    2.00<Δx.sub.TR /Δx.sub.WR <30.00

    0.30<a.sub.F /a.sub.Z <0.80.


2. A zoom lens system according to claim 1, wherein when ratios (dBf/da)of the amount dBf of infinitesimal movement of the imaging plane to anamount da of infinitesimal movement, in a direction of rotation, of saidfocusing lens unit on said focus cam at the infinity and closestin-focus points are respectively represented by γ_(a0) and γ_(aR), saidzoom lens satisfies the following conditional formula at least at thewide-angle end and the telephoto end:

    2.00<γ.sub.aR /γ.sub.a0 <10.00.


3. A zoom lens system according to claim 2, wherein when conversioncoefficients K_(a), which are expressed by K_(a) =ΔBf/Δa and areobtained when said focusing lens unit is located in lens arrangementscorresponding to the infinity in-focus state and the closest in-focusstate, are respectively represented by K_(a0) and K_(aR), said zoom lenssatisfies the following conditional formulas at least at the wide-angleend and the telephoto end:

    1.50<K.sub.a0 /γ.sub.a0 <6.00

    0.30<K.sub.aR /γ.sub.aR <0.80

where ΔBf: the defocus amount between an imaging position of an objectat an arbitrary position and a predetermined imaging point position Δa:the angle of rotation of said focusing lens unit on said focus camrequired for attaining an in-focus state on the object.
 4. A zoom lenssystem according to claim 1, wherein when ratios (dBf/da) of the amountdBf of infinitesimal movement of the imaging plane to an amount da ofinfinitesimal movement, in a direction of rotation, of said focusinglens unit on said focus cam at the infinity and closest in-focus pointsare respectively represented by γ_(a0) and γ_(aR), and conversioncoefficients K_(a), which are expressed by K_(a) =ΔBf/Δa and areobtained when said focusing lens unit is located in lens arrangementscorresponding to the infinity in-focus state and the closest in-focusstate, are respectively represented by K_(a0) and K_(aR), said zoom lenssatisfies the following conditional formulas at least at the wide-angleend and the telephoto end:

    1.50<K.sub.a0 /γ.sub.a0 <6.00

    0.30<K.sub.aR /γ.sub.aR <0.80

where ΔBf: the defocus amount between an imaging position of an objectat an arbitrary position and a predetermined imaging point position Δa:the angle of rotation of said focusing lens unit on said focus camrequired for attaining an in-focus state on the object.